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iMac G5: 2x512MB or 1GB+512MB

papersushi

papersushi

macrumors regular
Original poster
Nov 14, 2003
150
7
On iMac G5, Memory 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.

My questions is, should I go with 2x512MB to get 128-bit memory bus or more memory 1GB+512MB but with 64-bit memory.

Thanks!
 
go with 1gb * 2. Get it over with, max out.

if you go with 2*512, then you MIGHT eventually toss both.
if you go with 512, and 1024, you don't have a matched pair.

I just bought my recommendation from crucial for 110 a stick.

Now I just have to get the iMac!
 
Personally I would go with the 1GB + 512MB sticks of ram. I remember reading somewhere that the 128-bit memory bus isn't really that much of an advantage on Apple's current computers because it can't be fully used to it's potential. How much of that is true I'm not sure of, maybe someone else can clarify it for you.
 
If you don't want to splurge on 2GB of RAM just yet, just get the single 1GB stick to replace the 512MB one. That's what I did and that way you don't pay for the 512 either.

Then later on, if you want to, you can get the extra 1GB stick.
 
Go with the 1-1GB Dimm and the 1-512MB Dimm of RAM. That way when you decide to max out the memory later on you wont have to throw away 2 Dimms of RAM.
P.S.- I have read in macaddict magazine and elsewhere that running the DDR in the iMac G5 in pairs can result in performance boosts of up to 15%.
 
^^Then why are you recommending 1GB + 512MB? ;)

I'd either get the 2*512MB, or 2*1GB. If you're not doing anything hardcore anyway, I guess 1GB + 512MB isn't a bad way to go, but in terms of performance, get identical pairs. :)
 
I would actually recommend 2x1GB Dimms. But since papersushi is looking for one of the two options above I think the later is the better move because throwing away 2 512MB Dimms of RAM seems wastefull. Plus the performance boost gained from running the RAM in pairs is not that significant (ie- up to 15%)
 
dmw007 said:
I would actually recommend 2x1GB Dimms. But since papersushi is looking for one of the two options above I think the later is the better move because throwing away 2 512MB Dimms of RAM seems wastefull. Plus the performance boost gained from running the RAM in pairs is not that significant (ie- up to 15%)
Click to expand...

The biggest waste is getting anything more than the minimum from Apple.

the imac comes with 512
to upgrade to 1 1GB dimm costs $175, and 2 1-GB dimms $475 (so the second is $300)

From crucial, however, 1 1GB dimm costs $115, and a 512mb costs $53.

So, even if you have to toss the 512 dimm, you're better off than buying a 1GB dimm from apple.

In other words, figure out what you can afford now in terms of extra memory, and get it all from Crucial. If you decide you want more, just eat the DIMM they include, or sell it to someone who doesn't care.
 
Le Big Mac said:
The biggest waste is getting anything more than the minimum from Apple.

the imac comes with 512
to upgrade to 1 1GB dimm costs $175, and 2 1-GB dimms $475 (so the second is $300)

From crucial, however, 1 1GB dimm costs $115, and a 512mb costs $53.

So, even if you have to toss the 512 dimm, you're better off than buying a 1GB dimm from apple.

In other words, figure out what you can afford now in terms of extra memory, and get it all from Crucial. If you decide you want more, just eat the DIMM they include, or sell it to someone who doesn't care.
Click to expand...

Well put!
 
Get the 1GB stick, and upgrade to another of the same later. If you do get a 512MB stick, it has to be exactly the same as the one that's in there or you won't get the 128-bitness. Even then, as said, it's only about a 15% boost, if that. 1.5GB would be faster than 1GB + 15%.
 
I debated this issue when I first got my iMac G5. I had Apple install a 512 stick and ended up buying a 1GB stick to go with it. My iMac G5 never stalls and I hardly ever see the beachball......no matter what and how much I have going at one time.
 
papersushi said:
On iMac G5, Memory 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.

My questions is, should I go with 2x512MB to get 128-bit memory bus or more memory 1GB+512MB but with 64-bit memory.

Thanks!
Click to expand...


Barefeat's testing showed no real gain from matched pairs:
http://www.barefeats.com/imacg5d.html

So just buy whatever amount of RAM you think you need. I maxed my iBook out to 640 MB back in the fall of 2003 and it was great... when I got my iMac G5, I added a 2nd 512 MB stick for 1 GB and have never looked back!
 
well my new powerbook (which i'm on right now) has 2x512 RAM.

Was this a mistake? The computer has worked great, but am I in trouble in the future?
 
Why would you think that?

My understanding is that paired RAM chips do not offer any improvement over unpaired ones in anything but a G5 Mac, so unless you feel that at some point in the future 1GB RAM will not be enough I don't think you have any problem.

And you could always swap a 512 MB chip for a 1 GB later anyway
 
Josh396 said:
Personally I would go with the 1GB + 512MB sticks of ram. I remember reading somewhere that the 128-bit memory bus isn't really that much of an advantage on Apple's current computers because it can't be fully used to it's potential. How much of that is true I'm not sure of, maybe someone else can clarify it for you.
Click to expand...

The 128-bit RAM bus is a big deal. 15% increase in speed!

iSwift said:
well my new powerbook (which i'm on right now) has 2x512 RAM.

Was this a mistake? The computer has worked great, but am I in trouble in the future?
Click to expand...

No, the G4 can't handle a 128 bit bus anyways so just get as good as a computer as you can afford, and upgrade the RAM in stages later depending on cashflow.

The G5, on the other hand, being a 64-bit native CPU, can use either 64 or 128 bit RAM busses. Think of a 128-bit RAM bus as RAID for RAM.
 
So there's been a lot of talk, but I can't quite find a conclusion. I have the "Rev A" iMac that came with only 256MB of RAM. Would it make more sense to just add a 1GB stick, or get 2x512MB to have 1GB (and the matched pairs thing)?
 
2GB is better than 1GB (obviously). The small gain you might get from 2x 512MB and especially 2x 256MB isn't better than just having more RAM. 1.25 is fine, as is 1.5, but if you can afford it 2GB will be better than anything if you can afford it. Dual channel or not.
 
I checked out how much RAM was in the iMac G5's (2.0 Ghz) at my local Apple Store and they had them all with 768 RAM and they could handle anything. I opened photoshop,garageband, and all the Final Cut apps at once and it never showed a beachball. So if 768 RAM can handle all that then im sure 2x 512 will be even better. But when i get my iMac G5 i'm going for the 512+ 1 Gig setup (I think) :eek:
 
Le Big Mac said:
The biggest waste is getting anything more than the minimum from Apple.

the imac comes with 512
to upgrade to 1 1GB dimm costs $175, and 2 1-GB dimms $475 (so the second is $300)

From crucial, however, 1 1GB dimm costs $115, and a 512mb costs $53.

So, even if you have to toss the 512 dimm, you're better off than buying a 1GB dimm from apple.

In other words, figure out what you can afford now in terms of extra memory, and get it all from Crucial. If you decide you want more, just eat the DIMM they include, or sell it to someone who doesn't care.
Click to expand...

And don't forget OWC. They don't do the "cookies" pricing games that Crucial does.
 
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