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LOLZpersonok

macrumors 6502a
Original poster
Aug 10, 2012
724
18
Calgary, Canada
I recently grabbed a Power Mac G5, and I got it with 4.5GB of RAM: two 1GB modules, two 256MB modules and four 512MB modules.

I'm trying to upgrade it just for fun. I can swap three modules: replace the 256MB modules with 512MB modules and one 512MB module with one 1GB module. With this configuration, it'd be three 1GB modules and five 512MB modules.

It's my understanding that the modules need to be installed in pairs, but so far, every configuration of memory modules I tried has yielded no success. First, it dropped to 3GB of RAM, then 1GB and every one in between. I'm swapping the modules between slots to figure out which is correct.

I've also found a diagram online that displays the identifiers for the RAM slots, so I'm trying to match them up. Can someone help me out? Can I even do three 1GB modules?
 
Last edited:
If the machine has 8 slots then you match from center out.

So counting from the top slot, match the letters A, B, C and D;

1 - D
2 - C
3 - B
4 - A - start here

5 - A
6 - B
7 - C
8 - D

Does that make sense?

Make sure the RAM is both a match in size and speed e.g CL2.5, etc
[doublepost=1527517175][/doublepost]
Can I even do three 1GB modules

No, but you could use two of them or buy another one to have four.
 
If the machine has 8 slots then you match from center out.

So counting from the top slot, match the letters A, B, C and D;

1 - D
2 - C
3 - B
4 - A - start here

5 - A
6 - B
7 - C
8 - D

Does that make sense?

Make sure the RAM is both a match in size and speed e.g CL2.5, etc
[doublepost=1527517175][/doublepost]

No, but you could use two of them or buy another one to have four.
I already found a diagram of the slot identification, and after a bit more testing, I figured that it probably does have to be either two 1GB modules or four, so I just replaced the two 256MB modules with two 512MB modules. 5GB isn't very mentally satisfying, but it's better than 4.5GB. Thanks for the help.
 
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