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macsrus
Jul 28, 2004, 10:07 AM
I agree...

Single threaded apps will not benifit from a dual core...
Then again they also dont benifit from a dual processor either...

Fortunately for me, The only interest I have in the ppc is for use in clusters..
So the dual core CPU's would bring a benifit to me ..... Higher CPU density per rack.

Also a Dual (Dual)Core xserve will cost me less for my low latency interconnect too... since I would only have to buy 1/2 as many cards and Switch ports.

Hattig
Jul 28, 2004, 10:12 AM
Sheesh, and everyone's missing the obvious possibility that he was originally talking about an English soccer/football team named "news", in which case it would be "if these news are correct, they are the best team in Europe"

What? That makes no sense at all! "If these Arsenal are correct .." makes no sense, why would a non-existent team called "news" be?

It should be "If this news is correct ... " or "If these rumours are correct ...". Maybe "If these news articles are correct".

And English, even in the UK, has moved on a lot since Shakespeare. "If this news be correct" is bad grammar. You might as well say "If incorrect this news be" or something else equally silly.

AidenShaw
Jul 28, 2004, 10:14 AM
Also a Dual (Dual)Core xserve will cost me less for my low latency interconnect too... since I would only have to buy 1/2 as many cards and Switch ports.

Agreed. A dual-dual JS20 would kick b#tt for some applications - and you'd have 168 CPUs per rack (or 336 logical CPUs). The mezzanine IB or Myrinet card would give you the interconnect at a good price too.

Probably wouldn't do that well on LINPACK (Top500) though - unless the current FSB is replaced with something that scales to twice to four times the bandwidth.

jouster
Jul 28, 2004, 10:22 AM
And English, even in the UK, has moved on a lot since Shakespeare. "If this news be correct" is bad grammar. You might as well say "If incorrect this news be" or something else equally silly.

I'm just as guilty as anyone for posting on the grammar thing, but it's getting kinda old, no?

"If this news be correct" is not bad grammar - as someone pointed out earlier it's an example of the present subjunctive being used (correctly) in place of the indicative - but it is an extremely archaic usage, and is one that you are unlikely to encounter these days.

English is full of similar examples: as someone once said, jokingly: "The use of a preposition to end a sentence is an abomination up with which I shall not put!" This is grammatically correct, but, one hopes, won't ever be said!

How 'bout we all call it a day on the grammar front?

Hattig
Jul 28, 2004, 10:43 AM
I'm just as guilty as anyone for posting on the grammar thing, but it's getting kinda old, no?

How 'bout we all call it a day on the grammar front?

I was just working my way through the thread. It reminded me of a story recently on Slashdot that argued that Mac users were better with English grammar than non-Mac users, and I was thinking how much this thread was trying to disprove that theory.

Anyway, my guess for the PowerMac 2005:

1) Dual 3GHz 970DP, PCIe x16, DDR2-800. Either 2x1.5 GHz bus, or 3x1GHz.
2) Dual 2.6GHz 970DP, PCIe x16, DDR2-666. Either 2x1.3 GHz bus, or 3x900MHz (2.7Ghz).
3) Dual 2.2GHz 970DP, PCIe x16, DDR2-666. 2x1.1GHz bus, or 3x800MHz (2.4GHz).

ClimbingTheLog
Jul 28, 2004, 11:15 AM
Single threaded apps will not benifit from a dual core...
Then again they also dont benifit from a dual processor either...Sure they do.

OK, in theory, in a vacuum, a single threaded app won't benefit from SMP.

But that single threaded app doesn't run in a vacuum, especially on a mac.

It runs alongside the kernel, the display manger, whatever servers are going on, virtual memory, etc.

A smart kernel gives any thread the least-used CPU. A really smart kernel would give your CPU-intensive single-threaded app to one core, and keep system stuff on another. In a dual/dual setup it would have VM on one, display on another, your app on a third and servers on a fouth.

You see this on both macs and PC/linux machines - SMP machines are more responsive overall, even with single-threadded apps and at the same clock.

Yes there is a hit for context switching but it's noise in the system in the final analysis.

(note to the nut who goes on about me personifying task schedulers: it's a literary device, get over it)

AidenShaw
Jul 28, 2004, 12:35 PM
You see this on both macs and PC/linux machines - SMP machines are more responsive overall, even with single-threadded apps and at the same clock.

Responsiveness can be a misleading metric.

The dual might feel more responsive while your single-threaded app is running, but you might find an insignificant speedup in the amount of work that gets done. The system doesn't seem to slow down while doing the 30 CPU minute app, but the app takes exactly 30 minutes rather than 30 minutes and 20 seconds.

Clearly, if you often have more than one computing thread that needs a lot of CPU (whether it's multiple single-threaded apps or a multi-threaded app), the dual will be better.

If you have a single thread, the 4GHz single will tromp the 3GHz dual.

I'm not trying to simply argue, I just want people to realize that a dual is almost never twice as fast as a single. YMMV. Thanks for listening....

Supa_Fly
Jul 28, 2004, 07:46 PM
I agree...

Single threaded apps will not benifit from a dual core...
Then again they also dont benifit from a dual processor either...

Fortunately for me, The only interest I have in the ppc is for use in clusters..
So the dual core CPU's would bring a benifit to me ..... Higher CPU density per rack.

Also a Dual (Dual)Core xserve will cost me less for my low latency interconnect too... since I would only have to buy 1/2 as many cards and Switch ports.


OK I thought the whole point of ANY version of OS X and PowerMacs going to Dual Processors was the FACT that the OS will be able to distribute threads onto more than one processer. IS this a fact or is it a myth??? Please someone clarify. That said if its a FACT, then why can't single threaded apps benifit from Dual Processor, or even from Dual Core cpu's.

bonk
Jul 28, 2004, 08:03 PM
did no one laugh at my dual dual dual dual comment?



sigh

~Shard~
Jul 28, 2004, 08:10 PM
did no one laugh at my dual dual dual dual comment?



sigh

Evidently one person did. You. :cool:

And just a little piece of advice - it makes it look even worse when you have to quote your own post to draw attention to it. :p :cool:

macsrus
Jul 28, 2004, 08:20 PM
OK I thought the whole point of ANY version of OS X and PowerMacs going to Dual Processors was the FACT that the OS will be able to distribute threads onto more than one processer. IS this a fact or is it a myth??? Please someone clarify. That said if its a FACT, then why can't single threaded apps benifit from Dual Processor, or even from Dual Core cpu's.

Let me try to clarify this....

Programs by design can be either single or multithreaded....
Most applications are single threaded...
An operating system controls when and where an application's thread/threads are alotted CPU time.

Multithreaded apps can have their threads spread over multiple CPUs if a system has more than one CPU...
Single threaded apps do not benifit from multiple cpus.....

macsrus
Jul 28, 2004, 08:23 PM
Responsiveness can be a misleading metric.

The dual might feel more responsive while your single-threaded app is running, but you might find an insignificant speedup in the amount of work that gets done. The system doesn't seem to slow down while doing the 30 CPU minute app, but the app takes exactly 30 minutes rather than 30 minutes and 20 seconds.

Clearly, if you often have more than one computing thread that needs a lot of CPU (whether it's multiple single-threaded apps or a multi-threaded app), the dual will be better.

If you have a single thread, the 4GHz single will tromp the 3GHz dual.

I'm not trying to simply argue, I just want people to realize that a dual is almost never twice as fast as a single. YMMV. Thanks for listening....



True True

MikeBike
Jul 28, 2004, 10:49 PM
Let me try to clarify this....

Programs by design can be either single or multithreaded....
Most applications are single threaded...
An operating system controls when and where an application's thread/threads are alotted CPU time.

Multithreaded apps can have their threads spread over multiple CPUs if a system has more than one CPU...
Single threaded apps do not benifit from multiple cpus.....

Are you ready for this:
Most Apps are Multi-Threaded!
Go to Applications/Utilities/ and start Activity Monitor
Press AppleKey-1 which equals Show Activity Monitor

Now take a look at the currently running processes on your machine.
It's actually HARD to find a process running just 1 thread!

Finder uses 1
Palm Desktop Background 1
System Events 1

But, on the other hand:
My personal favorite: Borland JBuilder: 14
Safari: 5
Dreamweaver: 5
iTunes: 9 -- just playing a song in a play list!
Word: 5 -- just an open document
Powerpoint: -- 1 new doc open
Excel: 4 -- 1 new doc open

The days of running JUST StarRaiders on our Atari800's are over.

;)

Amdahl
Jul 29, 2004, 12:30 AM
If you have a single thread, the 4GHz single will tromp the 3GHz dual.

I'm not trying to simply argue, I just want people to realize that a dual is almost never twice as fast as a single. YMMV. Thanks for listening....

Actually, the dual is NEVER :eek: twice as fast as a single (of the same speed). The principles involved are described by Amdahl's Law.

ddtlm
Jul 29, 2004, 12:41 AM
MikeBike:

Most Apps are Multi-Threaded!
Yeah threads are an effective way to handle ansyncronous operations such as user interface, network IO, and file IO. However those handler threads are typically not doing anything remotely strenuous, they spend vitually every moment of their existance blocked, waiting for something to happen.

When people talk about multi-threaded things they tend to be talking about threads that speed things up, which the IO threads do not in a typical situation.

maxvamp
Jul 29, 2004, 01:11 AM
Most apps that people use Macs for are MULTI-THREADED.

FCP - Parallel renders
DVD SP - Parallel renders / encode-decode
Macromedia anything - multiple filters
Adobe Anything - ditto
iAnything - encode-decode ( iTunes ) parallel renders ( iMovie )
TOAST- Background renders and burning
XCODE - compilation, code assistance.
Cinema 4D - rendering
Maya - rendering
Any web browser, with the possible exception of lynx multiple downloads, parallel rendering of graphics
etc ( name many things ).

While YMMV, you shouldn't necessarily count on your **system** doubling in speed, but simply not bogging down as much when doing multiple things. The amount of parallel processing varies oddly enough by manufacturer, and some applications will be up to twice as fast. Average increase is between 50% -> 80% for many apps. Apple products have proven to be highly effective in threading, while adobe products seem to be the most inefficient. Corel Bryce has/had no threading what so ever so extra procs mean nothing for this application. Several publications from DV to Mac Addict to DMN has hi-lighted these apps and efficiencies at one point or another.

For those who want to stay with the position that DOS lives and most all apps are single threaded, please provide a list of popular Mac apps that are single threaded. I have given you one ( Bryce ). Another would be Access, but that is on Windows ( Strange for a DB to be that way ).

I still believe that for the MAC market, you will find a lot of main stream apps that will make a lot of use of dual core / dual procs.

Max.
:D :D :eek: :eek:

ddtlm
Jul 29, 2004, 01:50 AM
maxvamp:

You're way too excited about that. Only some programs are threaded, only some parts of those programs are threaded, only some of those parts are going to be able to use more than two processors, and even in cases where many processors are used, performance will never scale linearly with the number of processors. This is a case of serious diminishing returns.

The natural state of programs is single-threaded. There's nothing DOS about it, its just the natural state of things.

Little Endian
Jul 29, 2004, 05:35 AM
Getting a Dual Processor Machine is well worth it especially with Macs. Apple historically charges only $300 more for that second processor considering all other aspects of the configuration is equal. So when spending $1500-$3000 on a machine the cost of having that second processor is only about a 10-20% increase in price while performance should average to about 50% improved overall when you average common fucntions and applications.

http://barefeats.com/g5.html

http://barefeats.com/pm1000.html

maxvamp
Jul 29, 2004, 10:21 AM
I have thrown down the gauntlet.

Please provide a list of non threaded Mac apps.

I will agree that the programs I mentioned do not scale linearly. That is why I gave some general stats, of which none mentioned, or should have mentioned 100% increase. Yes, the entire program is not always heavily using threads, but many action of those apps are not time consuming. Those apps mentioned, however, generally do the threading when it counts. In this respect, they are notorious of reducing the time it take to render / compile.

For those trying to make a living with this prosumer machine, this is where it counts most.

( DOS == singleThreaded) && ( OSX != DOS );

Max.

jbro
Jul 29, 2004, 04:54 PM
All I want to know is - when can I get a G5 laptop?!!?!?

MikeBike
Jul 29, 2004, 05:45 PM
All I want to know is - when can I get a G5 laptop?!!?!?

I'll take a dual-core G4 Powerbook! ;)
If I could get one.

wdlove
Jul 29, 2004, 08:05 PM
All I want to know is - when can I get a G5 laptop?!!?!?

I think that you will see the G5 PowerBook long before the dual core.

~Shard~
Jul 29, 2004, 09:44 PM
All I want to know is - when can I get a G5 laptop?!!?!?

You'll be waiting another entire year by my guess. Possibly announced @ MWSF, not shipping until 3 months later. And that's if you're lucky, I could see them not even being announced until summer...

melgross
Jul 29, 2004, 11:14 PM
[QUOTE=macsrus]NT 3.1 was the first Windows NT (There wasnt a verson 1.0 thru 3.0)


Yes, I think we all know that. It's been called Windows NT for so long now that it's easy to forget when you are writing late in the evening. It wasn't really worth mentioning as it doesn't change the argument.

melgross
Jul 29, 2004, 11:23 PM
Melgross and Aiden,

You both are trying hard to take the original comments and skew them out of context to make an untrue point.

Threaded tasking happens all the time in many programs. Mail.app collects mail from multiple mailboxes at once while indexing and doing other tasks. Safari does not download graphics sequentially. Framworks used to build a program, such as a UI **is** part of that program.


Max.

I know what you're saying, but it doesn't get to the heart of the matter. The threads that we are talking about are threads that split the processing of the problem the program is working on, into two or more "chunks" to be worked on in parallel, such as video processing.

I wonder if people are reading this entire discussion, because these questions have been answered before, several times already, in fact.

I don't know how Aiden has the time to answer each question so promptly. I would love to, but don't have the time. Fortunately, he does it well.

ddtlm
Jul 30, 2004, 12:51 AM
maxvamp:

I have thrown down the gauntlet.
What are you trying to prove by comparing lists of programs? You've dug up some high-profile programs with intermittent threading, that doesn't say anything about how useful two processors are, or four processors would be. Like I said, its a case of serious diminishing returns, and you are way too excited about it.

Please provide a list of non threaded Mac apps.
Consider the applications that you didn't list. Games, for example. Most command line tools, compressors, encryptors, image viewers, pdf viewers. And in your list, web browsers and Toast don't count (nothing there takes meaningful advantage of multiple CPUs).

( DOS == singleThreaded) && ( OSX != DOS );
This is obnoxious. DOS implies single threads but single threads do not and never will imply DOS, or even anything bad. Single threads are the natural state of programs, and single thread performance will remain very important.

maxvamp
Jul 30, 2004, 10:33 AM
I have seen written several times on this thread alone that most, if not nearly all programs are single threaded. I then get told I am getting too excited.

This argument I cannot let stand, as the base argument that all apps are single threaded is absolutely not true.

Now, there is a difference between effective parallel processing, and just plain ole threading, but both can be very useful in a multi-threaded environment, such as OSX.

If an application can have a main thread, and several monitors, then the work load can be split across several processors , or time sliced if needed. If a user only ran one application at a time, multiple processors in this case would be a waste. I, however, make the stand that people do many things at once with their machines. They have iTunes playing while working on bills, maybe Word open, and using Safari to do some online banking.

While none of these apps will bring down a processor alone, the monitors they have , if each put into a single thread would bring down this system with just this select few apps open. Threading will keep the system responsive, even though the processors are not staying at 100%.

There are other aspects to threading besides driving the CPUs all at 100% for every action, and most apps now are multithreaded. To say otherwise, no matter what the context is a lie.

One final note. Several of you try to basically, indirectly use Amdahl's law (http://www.cis.temple.edu/~shi/docs/amdahl/amdahl.html) to try to say all apps are single threaded, and send the message that multiple procs are a waist. I have to comment that yes, while Amdahl said that there are diminishing returns form multi proc systems, there is still some performance to be gained. You do him a great disservice when making such comments. Read the link I have posted.

Max.

maxvamp
Jul 30, 2004, 10:55 AM
Consider the applications that you didn't list. Games, for example. Most command line tools, compressors, encryptors, image viewers, pdf viewers. And in your list, web browsers and Toast don't count (nothing there takes meaningful advantage of multiple CPUs).

The big reason people buy macs are not to sit at command lines, or play games. Those tasks are more for the UNIX and windows world. Toast does encoding to video, and has several offspring apps, such as Disk Doctor that make use of multi threading.

I think what needs to be defined here is the argument. Here are some facets of what this thread has become:

1. All apps are single threaded.
2. All apps are multi threaded.
3. Multi threaded apps donít make use of multiple processors.
4. Most multi threaded apps do not effectively make the best use of multi proc systems.
5. Only the science community can make use of multiprocessors.
6. Shakespeare don't know English right.

We should narrow our focus on the topic, because I am thinking at this point that arguments 1 -> 5 are stepping on each other. I only disagree with points 1, 3, 5, and 6.

Max.

Amdahl
Jul 30, 2004, 01:39 PM
'Responsiveness' of an interface has two elements: The size of a timeslice, and the event handling model. It has nothing, directly, to do with SMP. UNIX folks have long enjoyed 'responsiveness,' and x86 folks generally went through this phase of thread-obsession in 1992 when OS/2 2.0 was released; again when NT 3.1 came out in 1993, and again when Win95 brought threading to the average Joe.

You should note that SMP was not common at those times.

The primary reason for the increased responsiveness of these systems was that the GUI no longer ran in a single 'thread' or 'process' (these are almost the same thing to a CPU), therefore an app that spent a long time processing an activity would not prevent the GUI from updating or responding. I'm sure the old Macs suffered from this in some way.

The key factor of responsiveness at the OS-GUI level became how quickly a thread could become the active thread; the longer a timeslice given to a thread, the longer it takes for the next thread to get active. The tradeoff is that you can have very short timeslices, and then waste all of your CPU in the switching overhead. The only benefit you get from SMP is that since you obviously have twice as many timeslice switches, you can theoretically cut your response time in half. The tradeoff still exists though; instead of simply doubling your speed with the same number of context switches (one CPU twice as fast), you've doubled your speed, but also doubled your context switches (two CPUs, same speed). This is an example of Amdahl's Law.

Now, the event model is the other key factor, and it is generally a given that you are going to at least not kill the whole OS-GUI once you have a true multitasking OS. The app creator can continue the effort and ensure that the app itself never freezes its own GUI either by multithreading itself. This is not really done to benefit from SMP; the benefit is achieved on a single processor as well. The actual code of what the app does is not automatically multithreaded, even if some GUI threads happen to automatically be created by the frameworks. The programmer would have to decide it was worth the effort to write certain parts in a multithread manner, and it would still be subject to Amdahl's Law.

I'm not sure what 'monitors' are; perhaps you refer to Java VM, perhaps to waiting for something to happen in general. But they are almost never implemented as a continuous CPU intensive polling effort. Instead, they almost always end up simply waiting for the OS to inform them that something has happened. This requires very little CPU power.

It also is rare that apps are 'given' a single CPU (called CPU affinity). Solaris allows it(perhaps Linux 2.6?), but the application (or admin) also has to specifically ask for it. It is common on applications where the cache is more important than CPU speed; database is a common one. Instead, the usual process is that threads or CPUs end up hopping among CPUs, so the shorter your timeslices, the greater chance the CPU cache gets thrown out and wasted. Another example of Amdahl's Law.

The bottom line is that multithread responsiveness is not a justification for SMP; SMP is only worth it when you've got specific apps that do not suffer as much from Amdahl's Law, such as some of the video apps you mentioned. The industry is being forced into SMP by difficulty making a single CPU run faster. If SMP was better than faster CPUs, Intel would have happily sold twice or quadruple as many CPUs in each computer since 1996 when NT 4.0 started showing up on advanced users desktops.

I have seen written several times on this thread alone that most, if not nearly all programs are single threaded. I then get told I am getting too excited.
...
While none of these apps will bring down a processor alone, the monitors they have , if each put into a single thread would bring down this system with just this select few apps open. Threading will keep the system responsive, even though the processors are not staying at 100%.

There are other aspects to threading besides driving the CPUs all at 100% for every action, and most apps now are multithreaded. To say otherwise, no matter what the context is a lie.
...
Max.

maxvamp
Jul 30, 2004, 02:26 PM
Amdahl,

I don't entirely disagree with you. A classic example of an application that spawns more than 1000 threads is Exchange 2000. Multiple processors do not improve this applications by up to 100% per processor. Actually, most of those threads are just waiting to do something, kind of like sitting in a thread pool. iMovie on the other hand spawns a new thread for every mix edit you put on the timeline and actually starts a render in the background. Multiple procs will improve the time it takes for multiple renders.

As I was trying to point out in earlier posts, however, is that there is no shortage of dual processor multi threaded apps for the Mac platform. More fortunately, they happen to be the mainstream apps that people buy a mac for ( multimedia ).

One final point.

We need to determine context. If we talk about app specific threading and tasking, then on a per app basis, a multiple CPU system may seem to be a waist. For people doing multiple simultaneous things, the context changes. Since the OS is now dealing with more processes and threads, the system as a whole can make better use of multiple processors.

I guess it breaks down to this:

Grandma in Peoria writing an email probably won't see any benefit from dual procs, or anything above a 600 for that matter. She probably bought a Dell.

Grandson, though, working in the basement writing the next great program, or making millions through web design, or making the next great American film will clearly be able to make good use of both processors for the variety and number of tasks that he will be doing.

Son or daughter down at NIST will need XGrid **and** multi-procs to get their work done. They might need a generator too for all that extra power draw.

Max.

MikeBike
Jul 30, 2004, 05:23 PM
'Responsiveness' of an interface has two elements: The size of a timeslice, and the event handling model. It has nothing, directly, to do with SMP. UNIX folks have long enjoyed 'responsiveness,' and x86 folks generally went through this phase of thread-obsession in 1992 when OS/2 2.0 was released; again when NT 3.1 came out in 1993, and again when Win95 brought threading to the average Joe.

You should note that SMP was not common at those times.

The primary reason for the increased responsiveness of these systems was that the GUI no longer ran in a single 'thread' or 'process' (these are almost the same thing to a CPU), therefore an app that spent a long time processing an activity would not prevent the GUI from updating or responding. I'm sure the old Macs suffered from this in some way.

The key factor of responsiveness at the OS-GUI level became how quickly a thread could become the active thread; the longer a timeslice given to a thread, the longer it takes for the next thread to get active. The tradeoff is that you can have very short timeslices, and then waste all of your CPU in the switching overhead. The only benefit you get from SMP is that since you obviously have twice as many timeslice switches, you can theoretically cut your response time in half. The tradeoff still exists though; instead of simply doubling your speed with the same number of context switches (one CPU twice as fast), you've doubled your speed, but also doubled your context switches (two CPUs, same speed). This is an example of Amdahl's Law.

Now, the event model is the other key factor, and it is generally a given that you are going to at least not kill the whole OS-GUI once you have a true multitasking OS. The app creator can continue the effort and ensure that the app itself never freezes its own GUI either by multithreading itself. This is not really done to benefit from SMP; the benefit is achieved on a single processor as well. The actual code of what the app does is not automatically multithreaded, even if some GUI threads happen to automatically be created by the frameworks. The programmer would have to decide it was worth the effort to write certain parts in a multithread manner, and it would still be subject to Amdahl's Law.

I'm not sure what 'monitors' are; perhaps you refer to Java VM, perhaps to waiting for something to happen in general. But they are almost never implemented as a continuous CPU intensive polling effort. Instead, they almost always end up simply waiting for the OS to inform them that something has happened. This requires very little CPU power.

It also is rare that apps are 'given' a single CPU (called CPU affinity). Solaris allows it(perhaps Linux 2.6?), but the application (or admin) also has to specifically ask for it. It is common on applications where the cache is more important than CPU speed; database is a common one. Instead, the usual process is that threads or CPUs end up hopping among CPUs, so the shorter your timeslices, the greater chance the CPU cache gets thrown out and wasted. Another example of Amdahl's Law.

The bottom line is that multithread responsiveness is not a justification for SMP; SMP is only worth it when you've got specific apps that do not suffer as much from Amdahl's Law, such as some of the video apps you mentioned. The industry is being forced into SMP by difficulty making a single CPU run faster. If SMP was better than faster CPUs, Intel would have happily sold twice or quadruple as many CPUs in each computer since 1996 when NT 4.0 started showing up on advanced users desktops.

Intel has a long history of selling mhz delta's as a reason to buy.

I trust IBM to not be directed by the sales department, but by people competent in computer science.

I think that Java programmers and C, C++ programmers can and do make effective use of multiprocessor machines. It could be argued that the JVM is happiest and was really designed to run on a QUAD processor.

VB programmers still haven't caught on to multi-threading, so, on this point you are right. But, I believe the fault can be layed at Microsoft's doorstep.
Interesting that they Don't teach multithreading in the MCSD courses.
( Yes, I know they teach "How to use a Thread" in a Gui, but they don't teach "How to write a thread". )
I believe this is an interesting omission.

You bring up Databases, again another example of an application that can make effective use of dual processors: There's also web servers, plus the other apps mentioned.

It seems to me if you use any development tools or pro level app. there is a clear advantage to a dual core chip. Especially when all the chip builders are hitting the ceiling on ghz.

The question isn't would a dual core 750mhz processor be faster then a 1.5Ghz G4, but, would a Dual-Core 1.5ghz G4 be faster then a single-core 1.5ghz. I think the answer is yes.
;)

ddtlm
Jul 30, 2004, 08:16 PM
maxvamp:

I have seen written several times on this thread alone that most, if not nearly all programs are single threaded. I then get told I am getting too excited. This argument I cannot let stand, as the base argument that all apps are single threaded is absolutely not true.
So is this an counter-arguement to me? Cause I don't believe I've made any claims about everything being single threaded.

I, however, make the stand that people do many things at once with their machines. They have iTunes playing while working on bills, maybe Word open, and using Safari to do some online banking.
This is not a scenario that would show a dual being noticably much faster than a single.

There are other aspects to threading besides driving the CPUs all at 100% for every action, and most apps now are multithreaded. To say otherwise, no matter what the context is a lie.
Amdahl did a good job on this one.

Several of you try to basically, indirectly use Amdahl's law to try to say all apps are single threaded, and send the message that multiple procs are a waist.
If you are trying to argue with me, then you've totally missed my point. Note I keep accusing you being being too excited about it, which is a different thing than claiming that multiple processors are useless.

The big reason people buy macs are not to sit at command lines, or play games.
Well in that case I hope Apple likes its niche market making movies and whatnot.

MikeBike:

It could be argued that the JVM is happiest and was really designed to run on a QUAD processor.
I'm sceptical.

You bring up Databases, again another example of an application that can make effective use of dual processors: There's also web servers, plus the other apps mentioned.
Only matters for high-traffic servers, not workstations.

The question isn't would a dual core 750mhz processor be faster then a 1.5Ghz G4, but, would a Dual-Core 1.5ghz G4 be faster then a single-core 1.5ghz. I think the answer is yes.
How about a dual 1.5 vs a single 1.7 with a couple megs of extra on-die cache? Otherwise the dual is be larger and costs more. The single will be faster most of the time.

Amdahl
Jul 30, 2004, 11:07 PM
Yes, I think we are in general agreement. At this point, it is just down to which apps, which markets, and how much does it cost.

Amdahl,

I don't entirely disagree with you.
...
Max.

MikeBike
Jul 31, 2004, 05:55 PM
- I think there should be no doubt that the JVM would make effective use of a multiprocessor / much less a multi-core multiprocessor.
Remember, Sun has certified Java to run on a 72 processor Solaris box.
I mean what's the point if Java didn't successfully scale on such a beast?

I think people don't appreciate that java truely was designed for the enterprise arena. Especially, with more benchmarks coming in, indicating that the JVM produces faster code then most C/C++ programmers.
To beat the JVM on a server, you now Must Profile your code.
And even then there's no guarentee that your complied code will beat the JVM's compiled code, especially if you don't profile all the Hot Paths thru your app. I know in our small web app's there's at least 16+ "Hot Paths".

Anyway, a dual-core G4 laptop would make a he** of a platform for
developing java with JBuilder X -- ( JDataStore, MySql, Oracle, Openbase ), plus ITunes, Mail and ICal, IAddress and IChat all running at once.

It's good to be on Apple.

;)

Fukui
Jul 31, 2004, 06:33 PM
Especially, with more benchmarks coming in, indicating that the JVM produces faster code then most C/C++ programmers.
;)
What?!

ddtlm
Jul 31, 2004, 09:06 PM
MikeBike:

I think there should be no doubt that the JVM would make effective use of a multiprocessor / much less a multi-core multiprocessor. Remember, Sun has certified Java to run on a 72 processor Solaris box. I mean what's the point if Java didn't successfully scale on such a beast?
Note that this does not address the issue of any relevant Java application benefitting from 4 processors, and it does not address your possible implication that Java is potentially a better justication for many processors than C is.

I think people don't appreciate that java truely was designed for the enterprise arena. Especially, with more benchmarks coming in, indicating that the JVM produces faster code then most C/C++ programmers.
In some applications, at a large cost in memory and start-up time.

To beat the JVM on a server, you now Must Profile your code.
To make good Java code, some say must profile it as well.

Anyway, a dual-core G4 laptop would make a he** of a platform for
developing java with JBuilder X -- ( JDataStore, MySql, Oracle, Openbase ), plus ITunes, Mail and ICal, IAddress and IChat all running at once.
Why do people constantly equate "many applications == faster on many processors" when most of their applications have indetectably small processor usage? You'd almost certainly do a lot better with one faster processor, such as a G5. Further, I encorage you to shelve your fast dual-core G4 dreams. To quote the company making the product:

The e600 core is instruction set and pin compatible with the G4 core used in the award-winning, high-performance MPC74xx family of PowerPC processors
Its pin compatible... that means the same old FSB. Not exactly the beast of a processor some people have been expecting. Perhaps the e700 will come though on that.

http://www.freescale.com/webapp/sps/site/overview.jsp?nodeId=02VS0l72156402

MikeBike
Aug 1, 2004, 06:14 PM
Interesting thread.

It may very well be that a dual processor feels faster because the os enjoys not just 2 extra processors but the L1 and L2 cache that go with them.
So, a smart Os can keep twice the cache filled with the active processes.
But, it must implement some kind of cache/processor preference.

Still, I still can't help but believe a whole other processor, on the chip, would make Java run like greased lightening. Plus, all those Folding at Home guys would love 4 altivec units to really run up the numbers.
Just wonder what the heat penalty would be with Folding running everything at 100%.

Maybe a single processor would feel as fast if it had the extra cache memory to manage. Again, it comes down to your standard work load and how you work. But, if your head is always in a Pro application or two it seems a dual core processor would be advantagous.

I'm not worried about the performance of the e600. The G4 at 1.5 ghz is a bit faster then the G5 at 1.6. So, I won't have G5 envy unless IBM builds a dual-core G5 they can put into a laptop.

ddtlm
Aug 1, 2004, 06:54 PM
MikeBike:

Interesting thread.
Yeah, though the readership seems to have dropped off a lot. ;)

It may very well be that a dual processor feels faster because the os enjoys not just 2 extra processors but the L1 and L2 cache that go with them.
I'm still not seeing how 4 cores is gona do a lot for responsiveness vs 2 cores. The more I think about it, the more I am inclined to believe that IBM is not preparing a dual-core 970 and is instead working on a Power5-lite. Even with 2MB L2 it would still probably be smaller than the 970 dual core, while being more useful to most people.

Plus, all those Folding at Home guys would love 4 altivec units to really run up the numbers.
Yeah that would certainly keep the transistors flipping. I don't think F@H uses AltiVec though, seems like if it did there would be a big effect vs PCs.

I'm not worried about the performance of the e600. The G4 at 1.5 ghz is a bit faster then the G5 at 1.6.
Yeah thats a real shame in my humble opinion. I blame Apple's memory controller, a programmer I have spoken to online claims it has huge latency compared to the old G4 (DDR) controller, something like 100ns vs 135ns turn-around time. But in any case, that 166mhz FSB is eventually gona put the brakes on G4's ...

MikeBike
Aug 2, 2004, 06:55 AM
MikeBike:


Yeah, though the readership seems to have dropped off a lot. ;)


I'm still not seeing how 4 cores is gona do a lot for responsiveness vs 2 cores. The more I think about it, the more I am inclined to believe that IBM is not preparing a dual-core 970 and is instead working on a Power5-lite. Even with 2MB L2 it would still probably be smaller than the 970 dual core, while being more useful to most people.


Yeah that would certainly keep the transistors flipping. I don't think F@H uses AltiVec though, seems like if it did there would be a big effect vs PCs.


Yeah thats a real shame in my humble opinion. I blame Apple's memory controller, a programmer I have spoken to online claims it has huge latency compared to the old G4 (DDR) controller, something like 100ns vs 135ns turn-around time. But in any case, that 166mhz FSB is eventually gona put the brakes on G4's ...


Why would a Power5-lite be smaller than a 970( based upon the Power4 ? ).

Team Mac OS X has climbed from around 27 to 14 place in the ranks.
I'm abit surprised by the rapid rise. I would have thought that x86 folders would have migrated to AMD based systems and stayed in the race.

Intel's dual processors only get a 40% boost in performance.
I think AMD systems see more of an 80% boost in performance.

More cores also means more cache: each cpu will have it's own independent cache, and a properly written os should be able to keep a much higher level of cache "coheriency"?

Anyway it's nice to see Apple/Ibm stay in the race.
At least we have something to talk about.

FFTT
Aug 2, 2004, 07:22 AM
After reading through a combined 15 pages on this subject.

I am hopeful for a summary.

IF your current system was a bit old and tired, but still working fairly well
and you had saved for 3 years to purchase a new CPU............

Would you go ahead and purchase the current G5 2.5 system with the hope
that it will hold you for at least 5 years or WAIT just a bit longer
till the new improved
970MP dual cores are available?????

titaniumducky
Aug 2, 2004, 08:41 AM
After reading through a combined 15 pages on this subject.

I am hopeful for a summary.

IF your current system was a bit old and tired, but still working fairly well
and you had saved for 3 years to purchase a new CPU............

Would you go ahead and purchase the current G5 2.5 system with the hope
that it will hold you for at least 5 years or WAIT just a bit longer
till the new improved
970MP dual cores are available?????

You would have to wait till abut mid 2005...

Phinius
Aug 2, 2004, 09:33 AM
MikeBike:
I'm still not seeing how 4 cores is gona do a lot for responsiveness vs 2 cores. The more I think about it, the more I am inclined to believe that IBM is not preparing a dual-core 970 and is instead working on a Power5-lite. Even with 2MB L2 it would still probably be smaller than the 970 dual core, while being more useful to most people.

A dual-core 970FX would come in handy for Apple to move more seriously into the enterprise. The current 970FX, with its 250KB of L2, is limited as a server processor.

[mikeBike] But in any case, that 166mhz FSB is eventually gona put the brakes on G4's ...[/QUOTE]

The upcoming 90nm G4 won't have a 166Mhz FSB. I have seen a internal Motorola document that describes the next G4 as having DDR and DDR2 capability. That puts the FSB at far beyond 166Mhz. I would expect this chip to be announced withing the next two months and it could be either dual-core or just single core at that time, with the dual-core arriving somewhat later.

Phinius
Aug 2, 2004, 09:37 AM
You would have to wait till abut mid 2005...

Given Apple's history of announcing updates at major events, I'd expect a revised 970 to be announced in January and before that the 970FX should hit 3GHz. Apple has stated that IBM has told them the 970FX production problems would be aleviated in the fourth quarter of this year, so that should mean 3GHz chips. And no, the 970FX-MP chips are not likely to go beyond 3GHz.

Frobozz
Aug 2, 2004, 10:29 AM
I think it's important to note the role of specialized processors as the computing industry matures. In the early days of the GUI, when the Amiga was actually the far more supirior product, it achived this goal from a combination of efficient multitasking (software) and customized graphics subsytems/processors. Today, what the Amiga achived with several processors is all but consolidated into one GPU... but for years the GPU has been underutilized in a desktop environment-- until perhaps Mac OS X 10.4, code named Tiger.

With all the talk we have been hearing about multiple processors it is interesting to note that OS X 10.4 will be using the GPU to do a lot of mathematical computations that are specialized to the GPU. In other words, instead of using the CPU, which is not as good at GPU style computations, it will use the GPU to offload a significant amount of processing to do things in real time that would have slowed a CPU based solution to a crawl even a couple years ago. I think it's important to realize how monumental OS X's strides to offload CPU tasks to the GPU really is. The reality is that GPU's are far better at a lot of things than CPU's are.

The result is that we will see real world performance gains far exceed the simple scaling of CPU number and speed. I think the next generation of G5's will probably use a single CPU that is dual core, making the machines more affordable. They'll also be much faster than if we just scale today's machines with tomorrow's CPU GHz. And this approach makes sense, too! The human brain has several customized areas that deal with customized computation: visual, auditory, reflex, reason and logic, etc. Why not make out computers this way? It's a start, and I think we may see more computers take advantage of this kind of thinking.

The future looks bright for the Mac, if you ask me.

Frobozz
Aug 2, 2004, 10:35 AM
And no, the 970FX-MP chips are not likely to go beyond 3GHz.

What's your source? The articles that I have read seem to indicate the multi-core 970 will be introduced around 3GHz, not top out there. I think the 970mp is designed to replace the need for 2 individual CPU's, so if the next revision is 3GHz, then the multi-core 970 will be 3GHz. Now, I could be wrong. I'll admit that. But I don't think any of the above is far off the beaten path and is actually likely.

I don't care how much spin you put on it, unless they stop indicating GHz ratings on their computers there is no way Apple will release a machine with lower GHz or equal GHz as they have now and call it an upgrade-- no matter what the real world performance is. It's a markting nightmare.

Fukui
Aug 2, 2004, 10:42 AM
Interesting thread.

It may very well be that a dual processor feels faster because the os enjoys not just 2 extra processors but the L1 and L2 cache that go with them.
So, a smart Os can keep twice the cache filled with the active processes.
But, it must implement some kind of cache/processor preference.

Well, a smart OS would always be able to split multiple threads across a single CPU, so why couldn't a "really really really smart" OS split a single thread across multiple CPUs? It would be nice.

Frobozz
Aug 2, 2004, 10:43 AM
After reading through a combined 15 pages on this subject.

I am hopeful for a summary.

IF your current system was a bit old and tired, but still working fairly well
and you had saved for 3 years to purchase a new CPU............

Would you go ahead and purchase the current G5 2.5 system with the hope
that it will hold you for at least 5 years or WAIT just a bit longer
till the new improved
970MP dual cores are available?????

I would buy now, or wait until the new machines come out to buy a refurb unit. Even if they can achieve linear performance increases (didn't happen this time) the 3.0 GHz machine is only 16% faster. Last time the 2.0 to 2.5 GHz jump was 25% in GHz, but only about 16% in actual. So that means we could see a real world performance increase of roughly 10%. You won't perceive that difference in your day to day tasks. In fact, unless you're running rendering farms or long running tasks, 10% won't amount to much. If we were talking about a 2.5 to a 3.5 GHz increase, maybe that starts to make sense... but I wouldn't hold my breath on that! :-)

I would base your decision more on the other capabilities of the upcoming machines. Sadly, we don't have much... but I would say that since you're looking at keeping the machine for 5 years that you should consider expansion options more. The CPU speed won't be that big of a deal. Maybe the new ram would be if it were DDR2? Maybe a PCI-express graphics card bus? Aside from that stuff, not much will change in my mind. Maybe someone else has some ideas about architectural improvements, but I think most of them occured in the jump from G4 to G5 (already.)

nuckinfutz
Aug 2, 2004, 12:59 PM
A dual-core 970FX would come in handy for Apple to move more seriously into the enterprise. The current 970FX, with its 250KB of L2, is limited as a server processor.

Actually the PPC 970 has always had 512KB of L2 cache. The 970MP would double this to 1MB per core.

Even if they can achieve linear performance increases (didn't happen this time) the 3.0 GHz machine is only 16% faster. Last time the 2.0 to 2.5 GHz jump was 25% in GHz, but only about 16% in actual.

2.5Ghz to 3Ghz is a %20 increase. We will not be able to accurately compare the 2.5Ghz Duals to a 3Ghz Dual Core because of the cache size differences and faster chip to chip links in a dual core system. Also it seems that the 970MP may have lengthened some pipelines which would allow it to clock higher but would change the IPC.

FFTT
Aug 2, 2004, 02:06 PM
I would buy now, or wait until the new machines come out to buy a refurb unit. Even if they can achieve linear performance increases (didn't happen this time) the 3.0 GHz machine is only 16% faster. Last time the 2.0 to 2.5 GHz jump was 25% in GHz, but only about 16% in actual. So that means we could see a real world performance increase of roughly 10%. You won't perceive that difference in your day to day tasks. In fact, unless you're running rendering farms or long running tasks, 10% won't amount to much. If we were talking about a 2.5 to a 3.5 GHz increase, maybe that starts to make sense... but I wouldn't hold my breath on that! :-)

I would base your decision more on the other capabilities of the upcoming machines. Sadly, we don't have much... but I would say that since you're looking at keeping the machine for 5 years that you should consider expansion options more. The CPU speed won't be that big of a deal. Maybe the new ram would be if it were DDR2? Maybe a PCI-express graphics card bus? Aside from that stuff, not much will change in my mind. Maybe someone else has some ideas about architectural improvements, but I think most of them occured in the jump from G4 to G5 (already.)


I must admit that the 2.5 machine is already 8 times faster than my 300 MHz G3 tower and would probably hold up well, but that also makes me wonder which configuration would have a more lasting stability.
The individual water cooled 2.5's or the future, far more complicated dual core?

After waiting this long, another few months is nothing if the benefits of
waiting mean a significant long term improvement.

At this point it is not worth the expense to upgrade this system further.
So I will be getting something new soon.

Frustrated, Dazed and Confused

Sun Baked
Aug 2, 2004, 02:48 PM
What's your source? The articles that I have read seem to indicate the multi-core 970 will be introduced around 3GHz, not top out there. I think the 970mp is designed to replace the need for 2 individual CPU's, so if the next revision is 3GHz, then the multi-core 970 will be 3GHz. Now, I could be wrong. I'll admit that. But I don't think any of the above is far off the beaten path and is actually likely.

I don't care how much spin you put on it, unless they stop indicating GHz ratings on their computers there is no way Apple will release a machine with lower GHz or equal GHz as they have now and call it an upgrade-- no matter what the real world performance is. It's a markting nightmare.Considering the same source people were pointing at indicating that the IBM PPC970 is close to Notebook capable, and that dual core is an option -- Norman Rohrer, chief designer of the PowerPC 970FX (http://www.eweek.com/article2/0,1759,1617070,00.asp).

A dual-core version of the processor could also boost performance at slower speeds. Rohrer declined to confirm whether a dual-core PowerPC is on the company's roadmap, although he did say that a dual-core chip would remove some of the pressure to constantly push clock speeds higher.A single core would likely be the MHz speed demon, while the dual cores run at a significantly lower clock -- while operating at similar heat/power to each other.

MikeBike
Aug 2, 2004, 06:27 PM
The result is that we will see real world performance gains far exceed the simple scaling of CPU number and speed. I think the next generation of G5's will probably use a single CPU that is dual core, making the machines more affordable.

The future looks bright for the Mac, if you ask me.

HAY! I don't want to hear ANY talk about dropping 2 chips for 1, except in a low end model, in the Power Mac line. I want, no demand, to see, Dual-Core, Dual-Processor machines! I want my QUAD processor. Don't you wreck my dreams man.

maxvamp
Aug 2, 2004, 08:31 PM
Actually, I am fairly positive that iMacs, iBooks, and eMacs will not see a dual core. I would be surprised if the iBook even got a G5 any time soon, leaving the PB space only at a single core G5.

I mentioned it before, but here comes the bummer... Unless AMD starts pushing dual dual cores, I would more likely expect the PM to drop to one dual core chip, and the dual chips stay with XServes where the Scientist will make the best use of them.

I WANT MY XServe ???

Max.

Phinius
Aug 2, 2004, 10:16 PM
What's your source? The articles that I have read seem to indicate the multi-core 970 will be introduced around 3GHz, not top out there.

The 970 is based on the Power4 core. There is very little possibility that the PowerPC that is based on the Power core will pass the Power chips in frequency on the same process size. The Power5+ is expected to peak at 3GHz on a 90-nm process. Therefore, the 970 multi-core will not go beyond 3GHz on a 90-nm process size.

I think the 970mp is designed to replace the need for 2 individual CPU's, so if the next revision is 3GHz, then the multi-core 970 will be 3GHz. Now, I could be wrong. I'll admit that. But I don't think any of the above is far off the beaten path and is actually likely.

The reason for a dual-core is not only to move two separate processors onto one chip, but also to get more performance out of every chip made. Apple could use dual-channel memory for two chips as they do now and have two additional processors too boot.

I don't care how much spin you put on it, unless they stop indicating GHz ratings on their computers there is no way Apple will release a machine with lower GHz or equal GHz as they have now and call it an upgrade-- no matter what the real world performance is. It's a markting nightmare.

A IBM executive recently stated that scaling was dead and that increases in performance will have to come mainly from something other than frequency increases. Going to a dual-core chip, and adding SMT (Power5) are just two of the ways that IBM is adding performance without increasing frequency.

Phinius
Aug 2, 2004, 10:24 PM
Actually the PPC 970 has always had 512KB of L2 cache. The 970MP would double this to 1MB per core.

Your right. I miscued there.



2.5Ghz to 3Ghz is a %20 increase. We will not be able to accurately compare the 2.5Ghz Duals to a 3Ghz Dual Core because of the cache size differences and faster chip to chip links in a dual core system. Also it seems that the 970MP may have lengthened some pipelines which would allow it to clock higher but would change the IPC.

Don't expect the 970MP to go beyond 3GHz. It's unlikely that IBM will extend the 970 pipeline stages beyond what exists now. That's due to the 970 core being based on the Power4. Even the Power5 core does not have more pipeline stages than the Power4.

ddtlm
Aug 3, 2004, 12:15 AM
MikeBike:

Why would a Power5-lite be smaller than a 970( based upon the Power4 ? ).
One core vs two.

More cores also means more cache: each cpu will have it's own independent cache, and a properly written os should be able to keep a much higher level of cache "coheriency"?
Hard to say for sure, but I bet the trouble with keeping all the caches coherent overrules the benefit from there being more total cache space.

Phinius:

The upcoming 90nm G4 won't have a 166Mhz FSB. I have seen a internal Motorola document that describes the next G4 as having DDR and DDR2 capability.
And I linked to their web page where they declare in no uncertain terms that the e600 is pin-compatible. That means the same FSB. (Besides, one can claim current G4's support DDR memory... through the system controller.)

The 970 is based on the Power4 core. There is very little possibility that the PowerPC that is based on the Power core will pass the Power chips in frequency on the same process size. The Power5+ is expected to peak at 3GHz on a 90-nm process. Therefore, the 970 multi-core will not go beyond 3GHz on a 90-nm process size.
I don't see why a Power5 core can be used to judge the Power4-based 970, and in any case, the 130nm 970 did clock higher than the Power4 which topped out at 1.9ghz (130nm) so far. But yeah I'd agree with what your saying about the 970mp not making it past ~3ghz.

Phinius
Aug 3, 2004, 09:50 AM
And I linked to their web page where they declare in no uncertain terms that the e600 is pin-compatible. That means the same FSB. (Besides, one can claim current G4's support DDR memory... through the system controller.)

The G4 is moving to 2GHz and if you believe that it will still have a 166MHz bus, then you are in for a surprise. The G4 has a history of moving to a faster bus speed with the same pin count.

Also, the G4 currently only uses half the speed of DDR memory, even though Apple chooses to use for marketing reasons.

I don't see why a Power5 core can be used to judge the Power4-based 970, and in any case, the 130nm 970 did clock higher than the Power4 which topped out at 1.9ghz (130nm) so far. But yeah I'd agree with what your saying about the 970mp not making it past ~3ghz.

The Power5+ is expected to reach 3GHz on a 90-nm process and Steve Jobs announced that the 970FX would reach 3GHz. Doesn't that alone indicate something? I believe it's more than coincidence and no the Power5 does not have more pipeline stages than the Power4, so it is relevent to compare the topend frequency of the Power5 to the 970FX on the same process size.

Incidently, there should be about a 10-15% performance increase from doubling the 970 L2 cache and up to a 50% increase in performance from adding another processor to the chip. That on top of the 50% increase in frequency going from 2GHz to 3GHz.

The next round of improvements should either include a move to a Power5 based PowerPC chip on a 90-nm process or 65-nm process. That might give a performance boost of up to 30% for the SMT and another 30% from the process shrink.

It looks like Apple and IBM are aiming for about a 50-60% speed improvement for each version of the 9XX PowerPC chip that Apple is using.

Frobozz
Aug 3, 2004, 09:57 AM
The 970 is based on the Power4 core. There is very little possibility that the PowerPC that is based on the Power core will pass the Power chips in frequency on the same process size. The Power5+ is expected to peak at 3GHz on a 90-nm process. Therefore, the 970 multi-core will not go beyond 3GHz on a 90-nm process size.

Bah! The only scenario the above makes sense is a dual cpu dual-core configuration. I don't think we'll see it. If we do, it'd be held for all but the xServe and perhaps a high end PM G5 config.

I see your point, I just think the single CPU / dual-core at 3GHz as being far more likely. Aside from the cost reduction (?) the marketing required to remove GHz from the equation would be interesting. Think of it this way: if Apple releases a CPU, no matter how fast the cache, no matter how many cores, that is less than 3.0 GHz they will fail in the public's eye. I agree that it amounts to basically nothing in real world performance, as a 2.5 GHz chip or 2.8 GHz chip can easily outperform a faster clocked chip-- but Apple will have to make a big shift in it's markting like AMD and Intel are starting to do.

I agree that scaling is no longer the most viable speed increase for a CPU, too.

Fukui
Aug 3, 2004, 01:15 PM
The 970 is based on the Power4 core. There is very little possibility that the PowerPC that is based on the Power core will pass the Power chips in frequency on the same process size. The Power5+ is expected to peak at 3GHz on a 90-nm process. Therefore, the 970 multi-core will not go beyond 3GHz on a 90-nm process size.

Power4/5 are designed with reliability in mind more than just raw clockspeed. Example being thier thicker oxide gates which reduces clock speed but it can take higher temperatures, the 970 is more for higher clock speed but it may die earlier than a power4/5 based system, would you still be using your G5 after 15/20 years? 30? If the 970 passes the power4/5 in clock speed, thats fine, people who buy Power 4/5s need them for a reason, same with the G5; its different markets. We need speed, they need reliability+speed but reliability wins.

wdlove
Aug 3, 2004, 01:43 PM
I enjoy reading this thread, but it is well above my head. Don't understand all the abbreviations. I do agree that reliability is very important factor.

ddtlm
Aug 3, 2004, 11:16 PM
Phinius:

The G4 is moving to 2GHz and if you believe that it will still have a 166MHz bus, then you are in for a surprise. The G4 has a history of moving to a faster bus speed with the same pin count.
Hah, so 200mhz? 233mhz? It's not gona scale much. Pin compatible.

The Power5+ is expected to reach 3GHz on a 90-nm process and Steve Jobs announced that the 970FX would reach 3GHz. Doesn't that alone indicate something?
No.

I believe it's more than coincidence and no the Power5 does not have more pipeline stages than the Power4, so it is relevent to compare the topend frequency of the Power5 to the 970FX on the same process size.
Ah, now I haven't gone counting pipeline stages but yeah those could mean something... though we are talking about different cores so comparison of stages alone really doesn't settle it.

FFTT
Aug 3, 2004, 11:29 PM
Thinking to myself... Ignorance Is Bliss


This is enough to make anyone crazy.

2 weeks ago, the 2.5 would have been my dream machine.

Now that it's all too clear the individual dual processors
may soon go the way of the Dodo, I'm reluctant to buy anything.

Water cooled DOES seem to be much safer than trusting 9 cooling fans
for long term survival. Otherwise, I would have gone for a 2 GHz dually
months ago. I still can't help but worry about the long term effects
of so much heat causing premature system failures.

I just hope now that a dual core dually WILL be available soon.
And that long term reliability will not be an issue.

I am hopeful that the upcoming G5 iMac will give us a few more clues as to where things are going and how soon.

maxvamp
Aug 4, 2004, 12:52 AM
Thank you for the perspective.

I would love to have a Dual 2.0, but realistically, the next time I buy a Mac, I will be buying the fastest possible.

Why you ask?

Well, I have had un unfortunate luck of Macs lasting to damn long. I own 5 machines, which I replace / upgrade as they wear out or become unusable. As you can see below there seems to be too much longevity with Macs:

Main Servers

PM G3 300 ( CVS Store and File / Print server ) running Panther
Dual 1GHz PIII - Backup server and dev box ( I know, bad combo )

Workstation - Games

PM 733 DA - General stuff / video / dev / other ( GoBan )
Home brew Water Cooled AMD64 3000+ XP running games ( For the kids )
iBook G3 600 test machine / portable machine / internet box / Games

Due to the fact the Macs are still very productive ( damn Macs ) My next machine may end up being a Dual-Dual PM or G5 PB 17"

When it comes to faster ( Mac ) machines, what do you really need?

Max.

MikeBike
Aug 4, 2004, 08:28 AM
Power4/5 are designed with reliability in mind more than just raw clockspeed. Example being thier thicker oxide gates which reduces clock speed but it can take higher temperatures, the 970 is more for higher clock speed but it may die earlier than a power4/5 based system, would you still be using your G5 after 15/20 years? 30? If the 970 passes the power4/5 in clock speed, thats fine, people who buy Power 4/5s need them for a reason, same with the G5; its different markets. We need speed, they need reliability+speed but reliability wins.

I want to emphasize fukui's point.
An Enterprise Server is made immune to Cosmic Ray abuse.
Wider Traces, ECC Parity Checked memory so that your long running server isn't getting it's OS clobbered in memory while it's running. And your financial apps are accurate, and you aren't wasting your debug time on sporadic errors. These are the POWER chips.

Your consumer chips ( 970, FX ) don't have the wide traces, and ECC memory. As a consequence, they can clock HIGHER. But, you are not protected from sporadic errors, but, you wouldn't PAY for that kind of protection anyway. So, if the Power5 will clock to 3Ghz, then the 975? should go to at least 3.5Ghz.

Phinius
Aug 4, 2004, 09:59 AM
Your consumer chips ( 970, FX ) don't have the wide traces, and ECC memory. As a consequence, they can clock HIGHER. But, you are not protected from sporadic errors, but, you wouldn't PAY for that kind of protection anyway. So, if the Power5 will clock to 3Ghz, then the 975? should go to at least 3.5Ghz.

Ahh, but the 970 chips do have the same thickness of traces that the Power chips do. IBM didn't change it when they manufactured the 970.

The 970 does use ECC memory.

Phinius
Aug 4, 2004, 10:08 AM
Hah, so 200mhz? 233mhz? It's not gona scale much. Pin compatible.

Internal Motorola documents state that the 2GHz G4 will have DDR and DDR-2 capability, so you can double your bus frequencies above.

Ah, now I haven't gone counting pipeline stages but yeah those could mean something... though we are talking about different cores so comparison of stages alone really doesn't settle it.

The Power5 is followup to the Power4 and it doesn't have more pipeline stages than the Power4. Which means that IBM is getting the performance improvements from something other than frequency boosts coming from architectural changes. The Power5 will move to 3GHz from a process shrink and the use of strained silicon.

Apple does not have the sales volume, nor does IBM have the money losing gift giving heart to create a special higher frequency architectural core just for Apple's small marketshare. The 9XX PowerPC chips will have the same amount of pipeline stages as their Power4 or Power5 brothern. There will be a substantial frequency boost when IBM comes out with the Power6 in 2006, however. It's expected to reach 5GHz. Which would probably put the pipeline stages at about the same amount as the original Pentium 4.

ffakr
Aug 4, 2004, 10:09 AM
Ahh, but the 970 chips do have the same thickness of traces that the Power chips do. IBM didn't change it when they manufactured the 970.

i'm fairly certain that this is not the case. Do you have any evidence that the Power 4 and the 970 use traces of the same thickness? I'll look for something specific to contradict you later.. I'm a bit busy now.

The 970 does use ECC memory.
The 970 doesn't care what memory you use, the memory controller isn't on the chip. There are, however, NO macs with 970 chips that support ECC. The 970fx chip in the xServe supports ECC, but that is because the system chipset supports ECC memory.
I think the original poster of the ECC comment was making a broad point about the quality of enterprise servers vs. a Mac desktop.

Phinius
Aug 4, 2004, 10:15 AM
i'm fairly certain that this is not the case. Do you have any evidence that the Power 4 and the 970 use traces of the same thickness? I'll look for something specific to contradict you later.. I'm a bit busy now.


If I remember correctly, my traces thickness information comes from a series of 970 articles at Arstechnica.com where the author interviews a few IBM executives.

MikeBike
Aug 4, 2004, 02:59 PM
Ahh, but the 970 chips do have the same thickness of traces that the Power chips do. IBM didn't change it when they manufactured the 970.

Prove it.

It's time you did some research.
You obviously haven't been following the IBM/Apple press releases since the first G5 was announced and put into a Mac product. Why don't you look up how Server chip makers like Sun, HP and IBM build their products to protect against Cosmic Ray error hits, and then see if those characteristics are in Any consumer product from Intel, AMD or Apple.

FFTT
Aug 4, 2004, 10:23 PM
Speaking of research...

/http://www.microsoft.com/presspass/features/2002/jul02/0724palladiumwp.asp

Reading this made me start to wonder what Apple might have up their
trees and how the newer system architectures may further limit the users
freedom by installing DRM on a chipset level.

Would this be avoidable by purchasing the current systems?

Just asking

ddtlm
Aug 5, 2004, 12:53 AM
Phinius:

Internal Motorola documents state that the 2GHz G4 will have DDR and DDR-2 capability, so you can double your bus frequencies above.
Hmmm, the words "pin compatible" sound familiar? Also what's your fascination with repeating things to me? I heard your claims about DDR the first time, and I told you at even current G4's support it... through the chipset. They'll support anything through the chipset, in fact.

The Power5 is followup to the Power4 and it doesn't have more pipeline stages than the Power4. Which means that IBM is getting the performance improvements from something other than frequency boosts coming from architectural changes.
Those kinds of changes can effect clockspeed still, either up or down. You cannot count pipeline stages and draw solid conclusions.

Apple does not have the sales volume, nor does IBM have the money losing gift giving heart to create a special higher frequency architectural core just for Apple's small marketshare. The 9XX PowerPC chips will have the same amount of pipeline stages as their Power4 or Power5 brothern.
This doesn't address anything I said, nor does it address anything I thought to be true. I think the root cause of your confusion is facination with the number of pipeline stages. A lot of variables effect clockspeed, number of stages is only one of them.

FFTT
Aug 5, 2004, 04:36 AM
Prove it.

It's time you did some research.
You obviously haven't been following the IBM/Apple press releases since the first G5 was announced and put into a Mac product. Why don't you look up how Server chip makers like Sun, HP and IBM build their products to protect against Cosmic Ray error hits, and then see if those characteristics are in Any consumer product from Intel, AMD or Apple.

Tech update:

Tin foil hats will be provided with all new G5 iMacs :-)

ffakr
Aug 5, 2004, 01:21 PM
If I remember correctly, my traces thickness information comes from a series of 970 articles at Arstechnica.com where the author interviews a few IBM executives.

here is the link to the interview with Peter Sandon..

http://arstechnica.com/cpu/03q2/ppc970-interview/ppc970-interview-1.html

I don't see anything related to the thickness of the traces.

From everything I've seen, the Power5s continue to be manufactured in a more robust manner than the 970s.

Do you have any proof of your contention that the Power 5 is not designed to be more robust than the 970?

wdlove
Aug 5, 2004, 01:59 PM
Is it becoming the opinion of our technically knowledgeable members that the 2.5 should not be purchased. So would it be wise to wait for this new dual core? Do you expect them to be announced during MWSF '05?

maxvamp
Aug 5, 2004, 04:15 PM
You'll get none!!!

There always has been and always will be speculation on the next great thing.

People often wait for the next great thing, and never buy anything because as soon as they are ready to buy, something better is speculater to be just around the corner.

If you are in the market for the biggest and baddest Mac around, buy a 2.5 now. There is nothing wrong with it. If you will be ready for a new Mac next year, buy one then.

Don't base your purchase on what may be coming...

Max.

wdlove
Aug 5, 2004, 07:24 PM
You'll get none!!!

There always has been and always will be speculation on the next great thing.

People often wait for the next great thing, and never buy anything because as soon as they are ready to buy, something better is speculater to be just around the corner.

If you are in the market for the biggest and baddest Mac around, buy a 2.5 now. There is nothing wrong with it. If you will be ready for a new Mac next year, buy one then.

Don't base your purchase on what may be coming...

Max.

Thank you Max, so your not anticipating anything better at MWSF?

My current Power Mac G4 Dual 450 will be 4 years old September 1st.

My wife has been encouraging me to purchase, she is afraid that my Mac will quit soon. I'm ambivalent, when I hear about the dual core.

maxvamp
Aug 5, 2004, 07:35 PM
Considering that you may have the new machine for 4 or more years, I doubt that whatever comes out at the next Mac World may justify your wait.

Remember if you wait, you are speculating, based on rumor, that a Dual core will be here. I don't know if the risk, as well as the small increase in performance ( if any, as I don't know what you use your machine for ) will be worth it.

You decide, but I would buy now if needed. You can always ebay the new machine if something way better comes along.

Max.

Multimedia
Aug 5, 2004, 09:33 PM
Thank you Max, so your not anticipating anything better at MWSF?

My current Power Mac G4 Dual 450 will be 4 years old September 1st.

My wife has been encouraging me to purchase, she is afraid that my Mac will quit soon. I'm ambivalent, when I hear about the dual core.Dual 2.5 G5 Will Likely Be The Top Until Next Spring At Least.

Apple's priority is now getting the G5 PowerBook Out The Door early next year after getting the G5 iMac going in September.

So MWSF Jan 05 is likely to be the PowerBook G5 Premiere Event.

You missed the window after the new lineup was announced when you could get a refurbished original Dual 2 for $1999. :(

And why do you need a dual core G5?

FFTT
Aug 5, 2004, 09:56 PM
My current Power Mac G4 Dual 450 will be 4 years old September 1st.

My wife has been encouraging me to purchase, she is afraid that my Mac will quit soon. I'm ambivalent, when I hear about the dual core.


Your wife lets you spend money on something YOU actually want?
Cool!




:)

wdlove
Aug 6, 2004, 01:31 PM
Your wife lets you spend money on something YOU actually want?
Cool!
:)

Aren't most wife's very supportive?

From the above posts it sounds as though it could be a long wait for the next upgrade.