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I'm having problem with my PC. For some reason my OS and BIOS do not recognize the memory correctly, although it used to recognize it. I have 12GB but only 8GB recognized. I have Rampage III motherboard, which supports up to 24GB.

I'm running it on Windows 7 Home Premium and I have 2GB × 6 sticks.

If I use CPU-Z to verify it, and it shows 12GB for the memory.

Any ideas?

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migrated from serverfault.com Apr 11 '12 at 8:48

This question came from our site for system and network administrators.

    
What changed between when it worked and when it stopped working? – David Schwartz Apr 11 '12 at 7:28
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If the BIOS won't recognise the memory correctly then its a waste of your time worrying about what the OS can or can not see - it only knows what the BIOS tells it. – RobM Apr 11 '12 at 7:29
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Since Rampage III supports triple channel memory and I'm assuming 3x4GB sticks, you may want to try putting the last stick into a different slot and see if that changes things. Also, for the future, include your OS, the number of sticks of RAM, etc.. – Andrew M. Apr 11 '12 at 8:11
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Are you sure you are using Home Premium and not Home Basic as the limit for Home Basic is 8GB of RAM (opposed to 16GB for Home Premium)? – tombull89 Apr 11 '12 at 8:26
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It's not possible for CPU-Z to show 12GB if BIOS shows only 8GB. – Janis Veinbergs Apr 11 '12 at 8:50

I would try running either Memtest86 or Memtest86+ (they are very similar - Memtest86+ was "forked" from Memtest86 a few years ago). Both are available to download for free. These programs perform comprehensive tests on RAM.

I would try just testing 1 stick at a time and to be really sure, I'd also test each slot separately. It might take a long time, but it's the only way you can be sure.

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