iMac G5 memory configuration question
From what I can gather from looking at the BTO options for the new iMacs, the new iMacs have two slots for RAM. Unlike the G5 Power Macs, however, it doesn't appear that you have to install memory in pairs. For example, there are two different options for getting 1 GB of memory: 2 x 512 MB, or 1 x 1 GB.
All of the options that I see, however, imply that when you have both slots filled, both sticks of RAM are the same size: 2 x 256 MB, 2 x 512 MB, or 2 x 1 GB.
What I'd like to do is order the low-end $1299 model, as-is with 256 MB of RAM, then buy one 512 MB stick, and hopefully end up with 768 MB of total RAM.
Anyone know if this would work out?
All of the options that I see, however, imply that when you have both slots filled, both sticks of RAM are the same size: 2 x 256 MB, 2 x 512 MB, or 2 x 1 GB.
What I'd like to do is order the low-end $1299 model, as-is with 256 MB of RAM, then buy one 512 MB stick, and hopefully end up with 768 MB of total RAM.
Anyone know if this would work out?
Comments
With the single channel memory canal, the 1/3 bus ratio is more than enough to feed the mobo. This lower bus speed, is also an improvement in watt consumption and heat issue. As a result the whole Imac has just a consumption of 180 watts, compared to the 500 and more of the dualies.
The Imac are really an hybrid of a desktop and a laptop computer.
The good new with the Imac G5 is that it's standart DDR 400, with easy access to both slots. I have ordered two 512 MB DIMM, but the day (hypothetic) i will want to upgrade, I can use this DIMM in my dual.
"Modules may be installed one at a time for 64-bit memory bus. To support 128-bit memory bus, modules must be installed in like pairs."
So what does this mean?
You don't have to install in pairs....but it's better if you do?
Originally posted by piot
Extract from Kingston web site iMac G5 page :
"Modules may be installed one at a time for 64-bit memory bus. To support 128-bit memory bus, modules must be installed in like pairs."
So what does this mean?
You don't have to install in pairs....but it's better if you do?
I also wonder if it means that the base 256 MB would be more likely to be 2x128 instead of 1x256. By adding one 512 MB as I'm thinking of doing, might I only be going up to 640 instead of 768, because I'll have to pull out one 128 MB stick?
Edit: Following the above link, a single 256 MB stick is shown as the default memory configuration -- so no worries about 128 MB sticks.
Originally posted by piot
Extract from Kingston web site iMac G5 page :
"Modules may be installed one at a time for 64-bit memory bus. To support 128-bit memory bus, modules must be installed in like pairs."
So what does this mean?
You don't have to install in pairs....but it's better if you do?
Interesting, if it's true it's a new feature, and an improvement compared to the powermac G5. It will means that my G5 with two 512 MB module will have dual channel memory access. If it's true, it will means that the level of performance of the Imac G5 will be very near than the single 1,8 Ghz G5 (even better if the HD is faster).
The other good thing about this is that it is also $50 cheaper than buying 1 stick of 1 gig.
Originally posted by kcmac
So...it sounds like it may be better to get 2 sticks of 512.
The other good thing about this is that it is also $50 cheaper than buying 1 stick of 1 gig.
It's cheaper, but we just don't know yet if it is going to be faster.
Kingston DOES say that when installed as specially matched pairs, the new iMac G5 will enable dual channel memory access. But this is the first any company has mentioned this possibility. Not even Apple's website addresses this:
http://docs.info.apple.com/article.html?artnum=86814
I think we need to wait for clarification from others more in the know, or until people get these in their hands and are able to perform real world tests.
BTW, Apple has requested that www.macbidouille.fr remove their supposed first-ever XBench scores from their website. .. Don't know what this means. Memory performance on their 1GB (total for the machine) was excellent, - don't know if it had to do with the above. On the flip side, SATA performance was poor. But again, for whatever reason, the scores have been pulled.
Originally posted by BK0001
BTW, Apple has requested that www.macbidouille.fr remove their supposed first-ever XBench scores from their website. .. Don't know what this means. Memory performance on their 1GB (total for the machine) was excellent, - don't know if it had to do with the above. On the flip side, SATA performance was poor. But again, for whatever reason, the scores have been pulled.
Hmm, quite interesting for a product about to ship. Don't Apple want free advertisement? Or was it bad advertisement?
Originally posted by PB
Hmm, quite interesting for a product about to ship. Don't Apple want free advertisement? Or was it bad advertisement?
The Xbench test was supposedly performed on one of the iMac G5 machines at Paris Expo, so who knows if there may be some connection there.
I believe it's true, there is no explanations of the bad performance results of the HD of the Imac G5. I think that Apple use the same disk in both the towers and the Imac.
If it is all the 184 pin DDR 400 (3200) isn't it the same speed?
"If only one DIMM is installed, the memory bus is 64-bit. If two non-identical DIMMs are installed, there are two 64?bit memory buses. If two identical DIMMs are installed, the memory bus is 128-bit. Identical DIMM pairs have the same size and composition and provide the fastest and most efficient throughput."
Not sure what Apple's computers typically come with, but the new iMac has a 180W power supply.
Originally posted by Silas
So identical DIMM means any two PC3200 (400MHz) DDR SDRAM DIMMs of equal size (512+512, etc.), regardless of the vendor?
Right.
KCmac : good choice. It's also my choice, and it was also the case for the Imac G5 presented at Apple Expo Paris.
For their computing tasks, will more memory or less but matched memory be quicker. For instance, what if you have a single 512 stick? Would an additional 512 or a 1gig be the better upgrade? 1.5 gigs with a 64bit buss or 1 gig with a 128bit buss.
Imagine trying to explain that one to a clueless friend asking for advice...
Originally posted by dfiler
Interesting, now upgraders will have a dilema...
For their computing tasks, will more memory or less but matched memory be quicker. For instance, what if you have a single 512 stick? Would an additional 512 or a 1gig be the better upgrade? 1.5 gigs with a 64bit buss or 1 gig with a 128bit buss.
Imagine trying to explain that one to a clueless friend asking for advice...
No doubt.
Any idea what kind of performance boost we are talking?
I bought from Apple Store and decided that upgrading to 512KB was worth it, but upgrading to 1GB (1 DIMM) was not. THEN, I ordered a 1GB stick from www.transintl.com . Now I'm scratching my head. I'm certainly not going to change my Apple Store order (which I think would reset my ship date to something much later than 9/29).
I guess I will wait, use 1.5GB configuration initially, and lurk on these boards for somemeone to analyze the true difference...
Originally posted by BK0001
No doubt.
Any idea what kind of performance boost we are talking?
I bought from Apple Store and decided that upgrading to 512KB was worth it, but upgrading to 1GB (1 DIMM) was not. THEN, I ordered a 1GB stick from www.transintl.com . Now I'm scratching my head. I'm certainly not going to change my Apple Store order (which I think would reset my ship date to something much later than 9/29).
I guess I will wait, use 1.5GB configuration initially, and lurk on these boards for somemeone to analyze the true difference...
I can easily predict what will be your next move. You will replace the 512 MB DIMM by a 1 GB DIMM for a total of 2 GB.
In the PC world there is a huge difference between single and double channel memory bus : except a 5-10 % speed bump.
For the amount of memory : going from 256 to 512 make a huge difference (much more important than dual channel thing). Going from 512 to 1GB make a difference, but less important. Moving from 1 GB to 1,5 or 2 GB do not do a lot of diffence excepting in some situations, like runnng tons of applications simultaneously (but in this case a dual G5 is more appropriate) of manipulating huges photoshop files (of more than 150 MB). Same apply for 3 D rendering of big files (but I doubt that the Imac G5 is the perfect mac for this job).
All thing consider I think 2 512 MB DIMM will be a perfect balanced choice, the choice that Apple did for the iMac G5 presented at the Apple Expo Paris.