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iMac 1.8 Ghz G5 Benchmarks
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I take the FCP comments w/a large grain of salt, as no serious FCP user is going to run on 256M RAM. Even non-power applications and regular OS-use will significantly benefit the casual user at about 1G RAM, which you may not be aware of b/c of your hiatus from apple since os 9-- os x really handles memory much differently.
The mimimal RAM is an Apple *marketing* strategy, probably for pricing. Of *COURSE* it'll all be going slow w/only 256M RAM with the overhead of OS X and of launching FCP, and it sounds like you should know exactly why it slows down, so I won't explain the obvious.
As for RAM prices, yes the RAM is expensive, but most FCP users are probably knowledgeable enough to buy their RAM elsewhere. Identical OEM Samsung RAM can be had for normal prices, such as at OWC http://www.macsales.com .
The iMac G5 is uniquely positioned as a consumer's home machine, but WITH the options of being much more powerful. FCP-use falls into this second option. The minimal configuration allows for Apple to sell the units to casual home users, but also lets people hungry for more performance (but not willing to buy a G5 tower for wtvr reason) to opt for the extras. (Although yes, I admit Apple should probably include bluetooth & airport for even the casual user).
The mimimal RAM is an Apple *marketing* strategy, probably for pricing. Of *COURSE* it'll all be going slow w/only 256M RAM with the overhead of OS X and of launching FCP, and it sounds like you should know exactly why it slows down, so I won't explain the obvious.
As for RAM prices, yes the RAM is expensive, but most FCP users are probably knowledgeable enough to buy their RAM elsewhere. Identical OEM Samsung RAM can be had for normal prices, such as at OWC http://www.macsales.com .
The iMac G5 is uniquely positioned as a consumer's home machine, but WITH the options of being much more powerful. FCP-use falls into this second option. The minimal configuration allows for Apple to sell the units to casual home users, but also lets people hungry for more performance (but not willing to buy a G5 tower for wtvr reason) to opt for the extras. (Although yes, I admit Apple should probably include bluetooth & airport for even the casual user).
With all this talk about the energy saver processor preference, I have a question. What is the point of setting your processor to automatic instead of highest? It seems that things are running faster on people's computers when set to highest instead, so that would indicate to me that automatic isn't doing its job right. Shouldn't automatic let everything run as fast as it can, while never giving it more processor speed than it can use? So if something is only able to use 75% of the processors full potential that is what the processor runs at, but if it can benefit from that extra 25%, shoudn't "automatic" ramp up the processor to 100%?
what's up with this matched pairs of Ram thing?
Can someone tell me,
I don't know muach about the different ways you can install the ram.
It seems that the best way is to have some kind of matched pair in there.
So if I wanted to have around a gig, would i better better to buy a 1 gig stick and add it to the 256 from the factory, or ditch the factory ram and install a matched pair of 512s?. If it makes any difference, this would be for running audio apps like Logic with software instruments.
(excuse me if I'm not using the right terminlogy here!)
thanks
Can someone tell me,
I don't know muach about the different ways you can install the ram.
It seems that the best way is to have some kind of matched pair in there.
So if I wanted to have around a gig, would i better better to buy a 1 gig stick and add it to the 256 from the factory, or ditch the factory ram and install a matched pair of 512s?. If it makes any difference, this would be for running audio apps like Logic with software instruments.
(excuse me if I'm not using the right terminlogy here!)
thanks
The iMac G5 technical specs and iMac G5: Memory specifications do not say that you get a performance boost from installing RAM in paired sizes.
As far as I know, Apple always makes explicit mention whenever RAM should be installed in pairs for best performance, e.g., the Power Mac G5 instructions that say
For the iMac G5, I have seen no such statement, and I conclude that you do not get a performance boost from paired memory. So, the dairy giant, my understanding is that you can leave the factory RAM and install 1GB in the other slot.
If anybody has seen technical information to the contrary, please post.
As far as I know, Apple always makes explicit mention whenever RAM should be installed in pairs for best performance, e.g., the Power Mac G5 instructions that say
For the iMac G5, I have seen no such statement, and I conclude that you do not get a performance boost from paired memory. So, the dairy giant, my understanding is that you can leave the factory RAM and install 1GB in the other slot.
If anybody has seen technical information to the contrary, please post.
Matched pairs is faster- the G5 is a 64 bit chip, and therefore needs a 128 bit memory bus to operate at highest potential (64 bits in, 64 bits out). Standard RAM modules are 64 bit, putting different modules into the slots makes for two 64 bit RAM busses. Putting matched pairs in would allow the processor to address them as one big module, making for a 128-bit memory bus, and the machines should operate much faster that way.
It's reminiscent of the Performa 5200/6200 fiasco: the 32 bit PPC chip in there (the 603) was running off of a 32 bit bus (designed to take SIMMs, not in matching pairs), and was starving for memory. Effectively, the processor had to use one cycle to write into RAM, and one cycle to read from RAM- something that most computers can do in one cycle. That effectively halved the processor speed on those machines. Adding insult to injury, the cache on those chips was incredibly small, slowing down the machine even more. The iMac G5 doesn't have the cache problem, but RAM intensive tasks will make the iMac work far slower than it should if RAM is not installed in matching pairs.
It's reminiscent of the Performa 5200/6200 fiasco: the 32 bit PPC chip in there (the 603) was running off of a 32 bit bus (designed to take SIMMs, not in matching pairs), and was starving for memory. Effectively, the processor had to use one cycle to write into RAM, and one cycle to read from RAM- something that most computers can do in one cycle. That effectively halved the processor speed on those machines. Adding insult to injury, the cache on those chips was incredibly small, slowing down the machine even more. The iMac G5 doesn't have the cache problem, but RAM intensive tasks will make the iMac work far slower than it should if RAM is not installed in matching pairs.
Matched pairs is more of compatibility thing than anything else. You could one stick of Crucial PC3200 and then one stick of Generic PC3200, as long as two things were true:
1) Both are the same size.
2) Both can run the same timings (I heard the G5's run really loose timings like 8-3-3-3, but that may just be hearsay).
*other obvious things, being that the RAM is good (not defective or with errors)*
If it is true they run 8-3-3-3, there really shouldn't be many issues on RAM meetings those specs (it is VERY loose).
1) Both are the same size.
2) Both can run the same timings (I heard the G5's run really loose timings like 8-3-3-3, but that may just be hearsay).
*other obvious things, being that the RAM is good (not defective or with errors)*
If it is true they run 8-3-3-3, there really shouldn't be many issues on RAM meetings those specs (it is VERY loose).
According to these Apple Developer Notes, matched pairs of DIMMS provide the best performance.Doctor Q said:
I understand your explanation but I'd feel more confident if you or anyone could post a link to a page by an authoritative company (Apple or otherwise) that says this applies to the iMac G5. Since Apple sells it in a nonpaired configuration by default (one 256MB DIMM), without mentioning DIMM pairing in any specs I've seen, I'm still doubtful that it matters for performance.aliasfox said:
A link from the Apple iMac G5 Developer Notes is in my previous post, just above yours.Doctor Q said:
Thanks, MacinDoc! As you might guess, I was typing my reply while you submitted yours.MacinDoc said:
That seems to settle it once and for all. I hope the dairy giant has been reading this.
Which brings up the question of why Apple doesn't say this more prominently, in their tech specs, and why they don't offer matched pair configurations by default. At a minimum, they should mention the performance issue if you click "Learn more" in the online store when configuring an iMac G5's RAM.
Nope. I'm looking at the overall package and saying, "The monitor's good, the CPU's good, the RAM capacity's good, the GPU's a bit ordinary, but the system as a whole will meet my needs just fine at a reasonable price for what it is." I know what my needs are; I know what sort of specs will fill those needs; I know that the new iMac is well and truly above those specs.Converted2Truth said:
If it were a 486SX-33, I'd be saying "No way in hell." You're talking to a techie -- a programmer/sysadmin -- not a consumer who vaguely thinks that RAM is the hard drive, the CPU is the monitor, and the CD-ROM is a cup holder.
Doctor Q said:
I have indeed, thanks everyone.
So the question that remains to me is, would the matched pair of 512's be an advantage over the unmatched 256 + 1 gig?
would an extra quarter gig be more or less important than the matching issue
the dairy giant said:I have indeed, thanks everyone.
So the question that remains to me is, would the matched pair of 512's be an advantage over the unmatched 256 + 1 gig?
would an extra quarter gig be more or less important than the matching issue
The matched pair would be better I believe.
the dairy giant said:I have indeed, thanks everyone.
So the question that remains to me is, would the matched pair of 512's be an advantage over the unmatched 256 + 1 gig?
would an extra quarter gig be more or less important than the matching issue
Actually, that would very much depend on your pattern of useage
If you have few applications open, and each application with a relatively small footprint, you benefit more from the matched pairs ( one poster in another thread said 5-25% in general, but needed tests on iMac G5 to confirm that it was the case with the iMac )
If on the other hand you are using a program like FCE/FCP, Photoshop with 8 megapixel raw images etc, where you have a tremendous footprint, more RAM would be to your benefit, since you'd lose out on lesser ram and the matched speedup in the latency of swapping data in and out..
Of course, best of all would be 2x1GB chips
I'd say go for the 1GB chip, and upgrade to 2x1GB later on ( to get both more RAM AND the dual channel speedup ) when it's affordable.
That way, you also get a speed boost some time into the life of your iMac to prolong its value
toti said:
So I guess this is what would apply to using Logic, trying to get as many virtual instruments, audio tracks and effects as poss... plus samples being loaded into ram...
the dairy giant said:
Yes, it surely would. Reason barfs on me on a 2x1.25GHz G4 with 1.5GB RAM with around 30 instruments and 30 effects. My iBook barfs at 10 instruments and 5 effects
( 640MB RAM and one 1GHz CPU ) Of course some of that attributes to lesser CPU, but most of it to memory shortage...
need tests, and common sense
Note also that "unused" memory will be used for file caches and other things to speed the system, so the benefits of 1280 MiB over 1024 MiB can be subtle and not proven by simplistic benchmarking.
In addition to the memory footprint question, the bigger question is the percentage of improvement with dual channel.
One could very easily discover that some individual benchmarks do better with 1024 MiB, yet in real world use (multiple task, multiple applications,...) that 1280 MiB is definitely better.
Since we don't yet know how a single 1 GiB DIMM fares against 2*512 MiB, it's mostly conjecture at this point.
(ps: A post far back used the term "interlacing" to describe the dual channel. The right term is "interleaving" ("interlacing" is a video term).)
toti said:
Note also that "unused" memory will be used for file caches and other things to speed the system, so the benefits of 1280 MiB over 1024 MiB can be subtle and not proven by simplistic benchmarking.
In addition to the memory footprint question, the bigger question is the percentage of improvement with dual channel.
One could very easily discover that some individual benchmarks do better with 1024 MiB, yet in real world use (multiple task, multiple applications,...) that 1280 MiB is definitely better.
Since we don't yet know how a single 1 GiB DIMM fares against 2*512 MiB, it's mostly conjecture at this point.
(ps: A post far back used the term "interlacing" to describe the dual channel. The right term is "interleaving" ("interlacing" is a video term).)
That's true.
My ( personal ) experience is that video and audio programs generally benefit from more memory since they have tremendous amounts of data that have to be accessed in realtime. Yet it all comes down to the users useage pattern. Some of my music/video editing is just fine on an iBook..
PS: Love your music Dairy Giant
My ( personal
) experience is that video and audio programs generally benefit from more memory since they have tremendous amounts of data that have to be accessed in realtime. Yet it all comes down to the users useage pattern. Some of my music/video editing is just fine on an iBook..PS: Love your music Dairy Giant
the dairy giant said:
One option that you have: fire up Logic, load up the virtual instruments, etc., such that you have as much memory being used by it as you are ever likely to see. Yes, it's likely to be slow (especially if you're still on 256 MB of RAM), but that's not the point. Once it's all loaded up to the max (and your poor iMac is stumbling under the load), load up Terminal.app (Applications, Utilities), and run "top". You'll see a bunch of columns; the important one is "VIRT" (for the total amount of virtual memory used by a given process). Type "Fo" (case is important!) to change the sort order to memory used, then hit Return to go back to the top display.
You should see Logic at the top of the process list, and its memory usage. This should give you an indication of how much memory you need; if it's approaching around 8-900 MB, I'd suggest that you'll need more than 1 GB. If it's over 1 GB, well.
If it's hovering around the 600 MB mark, you should be fine with a matched pair of 512 MB sticks.If Logic isn't likely to be your biggest memory hog, adjust the above steps to suit. You should be able to grasp the general idea.
Thanks for that sjl and toti.
And thanks for the compliment on the music toti!
(I think if I get one of these iMacs I might notice the difference -- I am using a 400mhz G3 iMac to do music in Logic, Reason etc.... Slowly!)
And thanks for the compliment on the music toti!
(I think if I get one of these iMacs I might notice the difference -- I am using a 400mhz G3 iMac to do music in Logic, Reason etc.... Slowly!)