Powermac G5 does not recognize RAM past 4GB

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Powermac G5 does not recognize RAM past 4GB

I have a Powermac G5 dual 2.0Ghz (june 2004) and I upgraded the memory to 6 GB(1GBx6) of Kingston 1 GB DDR-400 PC-3200, and it seems to recognize only 4GB of the memory. Anyone know how to make it recognize all 6 GB? Thanks for your help in advance.

Powermac G5, Mac OS X (10.5.2)

Posted on Apr 4, 2008 7:58 PM

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Answer 1

Apr 4, 2008 8:51 PM in response to emaildwight

You have to install them in matched pairs going from the middle outward. See your manual.

If you stalled them from the top down, I can see how only 4 of those 1 GB modules would be in matched pairs.

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Answer 2

Apr 5, 2008 7:18 AM in response to emaildwight

Hi emaildwight-

Greetings and welcome to the Apple boards

This may help: Memory (DIMMs) Replacement Instructions

This may also help: How to identify Power Mac G5 DIMM slots

Not to overlook the obvious, make sure the RAM is seated firmly. If you have doubts about a particular pair of sticks, try swapping them to a known good location and see if they work there.

Luck-

-DaddyPaycheck

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Answer 3

emaildwight Author

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Apr 5, 2008 11:58 PM in response to emaildwight

Thanks for your help guys. I did install them from middle out and all are the same and matched. Any other ideas?

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Answer 4

Apr 6, 2008 1:18 AM in response to emaildwight

Install them one set at a time starting at 1GB x 2, until a set is NOT recognized. If it happens to be the last set, make the last set the middle set to see if going from 2GB to 4GB is not recognized (just to rule out a problem with the motherboard. Hopefully, you can identify a faulty RAM module pair (and it's not the third set of RAM sockets causing the problem). If it's a problem with one of the modules and if they are physically identical, you can determine which module of the faulty pair is bad by swapping modules with another pair.

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Answer 5

Apr 8, 2008 8:13 PM in response to Kenichi Watanabe

I have a similar problem. I upgraded from 4Gb to 8Gb, all OWC 1Gb sticks. System Profiler and Info show I have 8Gb, but Activity Monitor still only shows 4Gb. Is there a 4Gb limit on these systems under Tiger, or is there something I need to do to actually get at the extra 4Gb? Any help appreciated.

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Answer 6

Apr 9, 2008 11:45 AM in response to Sean Mccoy

Top also shows the full 8GB. Is there some intermittent bug in Activity Monitor that causes it to under-report the available memory?

Message was edited by: Sean Mccoy

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Answer 7

jagered

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28 points

Apr 9, 2008 4:26 PM in response to emaildwight

hey... haven't seen any activity here so is your problem fixed?

i agree that you need install the sticks 1 at a time and see which is the culprit giving you the problem. is the ram new? and from where? i have never personally had issues with new ram even if bought at a puter show... if you find one bad, any reputible puter store should have a memory tester, they can confirm if it is good or bad. i know it's a lot of b.s. but more ram is definitely better to have! good luck

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