PowerMac G5 won't register all ram

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Level 1

8 points

PowerMac G5 won't register all ram

Hi all.

I recently have been working on a PowerMac G5 which came with Tiger and 5.5GB of DDR2 SDRAM, but come accross a strange issue which I've read a few people with PowerMac G5 have. At first only 2.5GB of RAM would ever register, but now I can only get 3GB to show. I've cleared the NVRAM and PRAM to no avail, upgraded to 10.5.8 with all updates with no luck. I tried swapping the modules about and found that sticks only register with an identical stick in the same numbered slot on the other group. This is really confusing me, and I'm certain the sticks work, but I can't grasp what's going on.

Any help would be apprieciated.

Thanks,

Naoki

PowerMac, Mac OS X (10.5.8), PowerMac G5 Dual 2.3GHz

Posted on May 4, 2012 2:49 AM

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Answer 1

japamac

Level 7

24,400 points

May 4, 2012 3:26 AM in response to NaokiS

RAM must be installed in same size pairs from inside out. If you have 4 slots, the pairs are installed 2-1 1-2.

If you have 8 slots, the pairs are installed 4-3-2-1 1-2-3-4.

http://support.apple.com/kb/HT2248

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Answer 2

japamac

Level 7

24,400 points

May 4, 2012 3:29 AM in response to NaokiS

Additionally, if RAM is installed correctly and if the RAM is, in fact, guaranteed Mac compatible RAM (not PC value RAM), solder degredation may be the cause. Though typically affecting startup as well, RAM not reading has been reported.

Heating the logic board around the RAM slots with a hair dryer is a way to test this.

The area must be heated to hot to touch, then start the machine.

Be sure that RAM in use is Mac compatible.....

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