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caveman_uk

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Original poster
Feb 17, 2003
2,390
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Hitchin, Herts, UK
Note that I attributed the CS performance increase to x86-64's larger number of registers, and not the increased register width. On applications that do not require the extended dynamic range afforded by larger integers (and this covers the vast majority of applications, including games), the only kind of performance increase that you can expect from a straight 64-bit port is whatever additional performance you get from having more memory available. As I said earlier, 64-bitness, by itself, doesn't really improve performance for anything but the rare 64-bit integer application. In the case of x86-64, it's the added registers and other changes that actually account for better performance on normal apps like games.

Should Apple move from 32-bit PPC to 64-bit PPC, Mac users should not expect the same kinds of performance gains that x86 software sees from the jump to x86-64. 64-bit PPC gives you larger integers and more memory, and that's about it. There are no extra registers, no cleaned up addressing scheme, etc.

Article here (about x86-64 mostly)
 

748s

macrumors 6502a
Dec 14, 2001
692
31
Tiger Bay
...........actually account for better performance on normal apps like games.........


round my way normal apps ain't no games:confused:
 

Bear

macrumors G3
Jul 23, 2002
8,088
5
Sol III - Terra
The reason there is no cleaned up addressing scheme is that the PowerPC got it right the first time.

As for any other differences betweenthe G4 and the 970, we would have to see the current specs of the 970 to make comparisons. Items that affect performance (besides being 64 bit):
  • Number of instruction pipelines
  • length of pipelines
  • memory bus width
  • bus speeds
  • size (and speed) of the various caches.
  • number of registers
  • amount of physical memory the processor/system can address
I'm sure I left others off that list, and of course how much each of the above affects an application depends on each individual application.
 

caveman_uk

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Original poster
Feb 17, 2003
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Hitchin, Herts, UK
I agree, but a few people seem to think that somehow a 64bit 1.5GHz processor will be as fast as 32bit 3GHz processor. I've seen stuff to that effect in postings here. I posted this just to make the point that going to a 64bit processor isn't going to suddenly give Macs a massive performance increase. A scalable, well-designed processor and a chipset that can adequately support it just might ;)
 

kenohki

macrumors regular
Apr 26, 2002
136
0
Originally posted by caveman_uk
I agree, but a few people seem to think that somehow a 64bit 1.5GHz processor will be as fast as 32bit 3GHz processor. I've seen stuff to that effect in postings here. I posted this just to make the point that going to a 64bit processor isn't going to suddenly give Macs a massive performance increase. A scalable, well-designed processor and a chipset that can adequately support it just might ;)

I think Apple's marketing department had a lot to do with that. Those nice diagrams of AltiVec on their site apply to SIMD but not to regular 64-bit integer or floating point operations.

*Multiplication is much easier than computer engineering. :D
 

RIP

macrumors member
Jul 23, 2002
75
0
Phoenix, AZ
I think that

the 970 will improve performance dramatically. Ars is probably correct that 64bit computing may not yield any performance improvements, but the 8-way superscaler will. My point; Ars is specifically talking about 64bit computing and what it brings to the table, and that is it. So for those of you that concluded from reading the pages at Ars that the 970 won't boost performance much compared to the G4, keep in mind that there are a lot of other changes not specific to 64bit computing that are included with the 970 that will be huge for the Mac community.
 

Nemesis

macrumors regular
Re: I think that

Originally posted by RIP
the 970 will improve performance dramatically. Ars is probably correct that 64bit computing may not yield any performance improvements, but the 8-way superscaler will. My point; Ars is specifically talking about 64bit computing and what it brings to the table, and that is it.

Agree. Generally, Ars Technica is not right regarding 970. First of all, 970 is designed to be most effective in 2, 4, 8, 16 way systems, which will DRAMATICALLY increase the performance of overall system.

970 is a non-standard 64-bit processor, so all the predictions are in vain. It cannot be compared to 64-bit AMDs because they follow different way of computing.

This is especially true when thinking about what will Apple do to enhance 64-bit computing. They will surely innovate something that will left us bewildered and amazed.

;)
 

ddtlm

macrumors 65816
Aug 20, 2001
1,184
0
Nemesis:

Generally, Ars Technica is not right regarding 970.
I guess it's no big deal to just outright reject the opinions of informed people when those opinions contracdict your pre-conceived expectations?

970 is a non-standard 64-bit processor, so all the predictions are in vain. It cannot be compared to 64-bit AMDs because they follow different way of computing.
This is hand-wavy nonsense. As a relation of one of the more established lines of 64-bit processors, the PPC-970 is very much more of a standard 64-bit processor than the Hammer is.

This is especially true when thinking about what will Apple do to enhance 64-bit computing. They will surely innovate something that will left us bewildered and amazed.
Meanwhile, on the planet Earth...
 

ddtlm

macrumors 65816
Aug 20, 2001
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0
RIP:

the 970 will improve performance dramatically. Ars is probably correct that 64bit computing may not yield any performance improvements, but the 8-way superscaler will.
Exactly!
 

porovaara

macrumors regular
Mar 7, 2002
132
0
sf
Re: Re: I think that

Originally posted by Nemesis
Agree. Generally, Ars Technica is not right regarding 970.


Uh huh, and how is exactly is Ars not right? I'm thinking you probably have no idea what the bulk of the articles on ars are even about.

Ars is completely and totally right with what is expressed in that article about the 970.
 

MacBandit

macrumors 604
8-way superscaler doesn't do you any good unless they are using multiple processors. While it is a good chance that they will (IF THEY USE THE 970 AT ALL) it doesn't mean they will use more then 2 processors as they are doing now. Remember these chips still cost money and Apple needs to compete on price 1st.
 

szark

macrumors 68030
May 14, 2002
2,886
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Originally posted by Bear
As for any other differences betweenthe G4 and the 970, we would have to see the current specs of the 970 to make comparisons.

Look to Hannibal's PPC 970 article and IBM's PDF for the answers.

This article (x86-64) was very informative, and he is right in saying that we would not see any performance increase based on the move from 32 to 64 bits. We will see a performance improvement from better clock speed/scaling, faster FSB, and the improved core.
 

caveman_uk

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Original poster
Feb 17, 2003
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I fear that some people are going to be horribly disappointed when the 970 comes out. It'll be better than the G4 - yes. Faster - yes. More scalable - yes. But to say
This is especially true when thinking about what will Apple do to enhance 64-bit computing. They will surely innovate something that will left us bewildered and amazed.
is being a little naive and optimistic. Apple are great designers but they can't turn water into wine...
 

Nemesis

macrumors regular
Re: Re: Re: I think that

Originally posted by porovaara
Uh huh, and how is exactly is Ars not right? I'm thinking you probably have no idea what the bulk of the articles on ars are even about.

Ars is completely and totally right with what is expressed in that article about the 970.

From the technnical point of view, they are right. I don't say they are wrong in that sense.

But the real world application of 970 is something different. That's what they didn't bother to talk about, because it is impossible to predict. Do we know how Apple will utilise 970? And do we know if Apple will use it at all?

For example, if Ford produces a V6 engine that is really nice but doesn't improve car speed drastically (from the point of view of general automotive industry), we are observing just the engine.

Of course that V6 will hardly beat V8 models, but it's the car and overall concept of a car that counts, not just engine.

Most of us buy car thinking how safe it is, what's the fuel consumption, is it affordable, does it looks nice, what's the standard equipment included, what's it's colour ... I think, the EXACT type of the engine and how it's built, which alloys it uses and does it produces 15 or 25 more kWs than a standard V6 (let's presume there is one) is totally unimportant for the majority of customers.

Tell me if I'm wrong. Producing a car that runs certain engine is what Apple is doing with 970 (let's presume they will use it). It's the car that matters! We'll be driving cars, sitting in a comfortable chair, with air-con, listenning to the nice music ... we won't be sitting with our asses on a overheated V6.

That's what I meant to say. Sorry for the confusion. ;)
 

Nemesis

macrumors regular
Originally posted by caveman_uk
I fear that some people are going to be horribly disappointed when the 970 comes out. It'll be better than the G4 - yes. Faster - yes. More scalable - yes. But to say is being a little naive and optimistic. Apple are great designers but they can't turn water into wine...

Probably not :), but I think 970 wouldn't exist at all if it wasn't Apple that delivered specifications and design improvements to the existing IBM PPC family and asked IBM to invest R&D money into a new project (that will open new markets).

So, if that is true, let's say this: if they gave the specs and how 970 will be designed, they must have someting in their minds on how to utilize its performance:
1. to the max
2. in the future
 

Nemesis

macrumors regular
Originally posted by MacBandit
There are too many assumptions going on here for any real logic to be derived.

If science worked like this we would have sailed off the edge of the earth a long time ago.

You're right. All we have to play with is pure guessing.

But I'd say that's cool as well, because by exchanging ideas between ourselves, we're actually participating in a huge brainstorming process that can shed some light on the future of our beloved platform.

I say, let's play and let's be provocative, thinking out of the box. Someone will say that we are just imagining things, but let's observe it as well:

"Imagination will often carry us to worlds that never were. But without it we go nowhere."
-- Carl Sagan
 

MacBandit

macrumors 604
Originally posted by Nemesis
You're right. All we have to play with is pure guessing.

But I'd say that's cool as well, because by exchanging ideas between ourselves, we're actually participating in a huge brainstorming process that can shed some light on the future of our beloved platform.

I say, let's play and let's be provocative, thinking out of the box. Someone will say that we are just imagining things, but let's observe it as well:

"Imagination will often carry us to worlds that never were. But without it we go nowhere."
-- Carl Sagan

That's fine but you need to keep it grounded in facts.

If we were to just make assumptions I would say right now that the PPC970 will you quad core and have 18 pipelines/core and each core would have it's own FSB.

Can you see the logic. What I said is not based in fact or reality at all just like most of the posts on the 970. Brainstorming is far more effective when you work from a solid base facts.
 

greenstork

macrumors 6502a
Jan 5, 2003
617
0
Seattle,WA
Look I don't claim to know much about this subject but from what I have read it seems like even if Ars' article is true about 64-bit integer computations and actually processor speed, isn't the biggest speed improvement on the Macs going to come from the scaled up bus speed 533 MHz or more I don't know exactly but that is what I have read.

The bus is what is currently clogging the ability of the processor and more importantly, the ability of the DDR Ram to use both the uptick and downtick of the clock cycle as it was intended. The 166 MHz bus currently on Powermacs nullifies the DDR memory.

For all those supposed tech savvy people on this thread panning the anticipated speed increases of the 970 and saying it will disappoint, I would think the improved bus speed alone and full utillization of DDR will provide drastic speed improvements.

Just my two cents
Dave
 

MacBandit

macrumors 604
Originally posted by greenstork
Look I don't claim to know much about this subject but from what I have read it seems like even if Ars' article is true about 64-bit integer computations and actually processor speed, isn't the biggest speed improvement on the Macs going to come from the scaled up bus speed 533 MHz or more I don't know exactly but that is what I have read.

The bus is what is currently clogging the ability of the processor and more importantly, the ability of the DDR Ram to use both the uptick and downtick of the clock cycle as it was intended. The 166 MHz bus currently on Powermacs nullifies the DDR memory.

For all those supposed tech savvy people on this thread panning the anticipated speed increases of the 970 and saying it will disappoint, I would think the improved bus speed alone and full utillization of DDR will provide drastic speed improvements.

Just my two cents
Dave

There will definitely be an increase in speed due to a faster FSB. Though it will not be as great as some would hope. On the X86 platforms the speed increase after several revisions was no more then about %15-%20. While that is a large increase it will not be that great on the Macs. There are a couple of reasons for this. The G4s are a much much more efficient in the way they hand data input/output. Also the G4 has a large L3 and L2 caches. Another things to consider is the architecture of the X86 platform requires the processor to process every last bit of data that goes through it. There is no DMA (direct memory access). DMA allows the Mac to move data from the hard drive to the ram to be accessed later without having to stream through the processor. DMA can access the DDR ram at full DDR speeds. Thusly the only speed increase will be a very minor one of normal cpu processes between the CPU and the system bus and not an increase in the rest of the computer processes.
 

Nemesis

macrumors regular
Originally posted by MacBandit
That's fine but you need to keep it grounded in facts.

If we were to just make assumptions I would say right now that the PPC970 will you quad core and have 18 pipelines/core and each core would have it's own FSB.

Can you see the logic. What I said is not based in fact or reality at all just like most of the posts on the 970. Brainstorming is far more effective when you work from a solid base facts.

What about this:

* Apple will introduce Mac models that won't use hard-drives but 3D optical memory (already working at IBM - technology exists), which is WAYS FASTER than using regular HDs and magnetic memory.

* FSB will run on 900 MHz (next gen buses - this also exists).

Will that improve the performance of next gen computer running single core 970?

We are constantly forgetting simple fact: Apple is the company that introduced the real life usage of ones of the most innovative concepts in computer industry that no other company dared to use: GUI, Mouse, CD, USB, FW, ... to say the few.

I'm just provocative. But all this can be true.
 

Rincewind42

macrumors 6502a
Mar 3, 2003
620
0
Orlando, FL
Originally posted by MacBandit
8-way superscaler doesn't do you any good unless they are using multiple processors. While it is a good chance that they will (IF THEY USE THE 970 AT ALL) it doesn't mean they will use more then 2 processors as they are doing now. Remember these chips still cost money and Apple needs to compete on price 1st.

8-way superscaler has nothing to do with how many processors are in the box, it is how many instructions that a single processor can have executing at any particular time.

Otherwise, the benchmarks on the 1.8 part put it at the level of a 3Ghz P4. Apple will probably drop 2 in a high end PowerMac and call it a day when these are released. How it will fare against a Hammer/Opteron I have no idea (I haven't seen benchmarks on those chips) but it will be fast, and it won't be because it is a 64-bit chip.
 

ddtlm

macrumors 65816
Aug 20, 2001
1,184
0
MacBandit:

8-way superscaler doesn't do you any good unless they are using multiple processors. While it is a good chance that they will (IF THEY USE THE 970 AT ALL) it doesn't mean they will use more then 2 processors as they are doing now. Remember these chips still cost money and Apple needs to compete on price 1st.
You don't know what superscalar means. I see that Rincewind42 told you just now, though.

There are too many assumptions going on here for any real logic to be derived.
I don't agree.

Nemesis:

You're right. All we have to play with is pure guessing.
Speak for yourself; some of us here know what we are talking about.

MacBandit:

If we were to just make assumptions I would say right now that the PPC970 will you quad core and have 18 pipelines/core and each core would have it's own FSB.
There is absolutely no mystery here. The PPC-970 is single core, the number and nature of its pipelines have been stated in that pdf from IBM's site as well as numerous articles and documents about the Power4, and we know that each processor has its own FSB.

There will definitely be an increase in speed due to a faster FSB. Though it will not be as great as some would hope. On the X86 platforms the speed increase after several revisions was no more then about %15-%20.
Compare a fast Athlon on a KT133A to the same chip on a nForce2 (you could do as high as a 2100+ or 2200+ on both I think). Big difference (on games and other relevant test). Since each new motherboard, each new bus speed, and each new processor makes only a small increase it is easy to be fooled and think that the FSB and memory are irrelevant, but in fact they are not. I know Aceshardware has done a few articles that illustrate parts of this.

The G4s are a much much more efficient in the way they hand data input/output.
Unsubstantiated claim.

Also the G4 has a large L3 and L2 caches.
Large L3 yes, but the L2 is actually undersized compared to the compedition which is all either at 512k or has at least newer chips there.

There is no DMA (direct memory access).
There is no DMA on what? PC's? PPC-970 systems?
 

jettredmont

macrumors 68030
Jul 25, 2002
2,731
328
Originally posted by MacBandit
8-way superscaler doesn't do you any good unless they are using multiple processors. While it is a good chance that they will (IF THEY USE THE 970 AT ALL) it doesn't mean they will use more then 2 processors as they are doing now. Remember these chips still cost money and Apple needs to compete on price 1st.

Also, note that 2 970s on a motherboard will cost significantly more to design and produce than 2 G4s on a motherboard as each 970 has its own FSB to the controller chip (and the controller chip hence has to manage multiple FSBs to CPUs instead of just one shared FSB ...)

Dual 970s will carry a significantly higher premium (either passed on to the consumer or eaten by Apple via lowered margins, yeah right) over single 970s than dual G4s carry over single G4s.
 

Nemesis

macrumors regular
Originally posted by ddtlm
MacBandit:


You don't know what superscalar means. I see that Rincewind42 told you just now, though.


I don't agree.

Nemesis:


Speak for yourself; some of us here know what we are talking about.



Oh, so, you work for Apple, right?

C'mon! Yes, you're talking techno stuff, but does it have anything with reality? Did Apple announce 970, dual 970, 64-bit Panther, or whatever....?

Nope.

So welcome to the rumor club, dude.
 
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