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I just built my first PC and only 8 of 16 GB Ram shows up on the system. I took out all of the RAM and put it in a different order, turned it on and 16GB Ram showed up. But when I restarted the computer, it was back to 8 GB. Is this a memory, motherboard, or OS problem? Here are the components in the computer:

  • RAM: 4GBx2 Mushkin 996770 DDR3 1333 (2 orders of this)
  • PSU: Corsair CMPSU-750HX 750W RT
  • CPU: Intel Core-i5 2500K 3.3GHz
  • HDD: 1TB Samsung HD103SJ
  • OS: Windows 7 Ultimate
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  • Try running software like Memtest86 to make sure that all of the RAM works
  • Check in the BIOS if it displays the full amount of RAM. If it does show the full amount in the BIOS, but not in Windows, it may be an OS problem. If it does not show the full amount in the BIOS, it is definitely a hardware problem
  • I checked; your processor and motherboard both support up to 32GB of RAM, so it's not a compatibility problem
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I shut down to check the RAM in the BIOS and it showed 16384 MB. Before it was abou 8000 GB. And now the 16 GB shows up in Windows Control Panel. Unfortunately, I think it will go back to 8 GB again. So can Memory be faulty? Or is it the Motherboard? btw, thanks for the feedback – Ethan Mar 8 '11 at 5:51
I think you probably mean 8000MB. If it said 8000GB, something is definitely wrong ;). The next time the wrong amount appears in Windows, reboot and check the BIOS. If the problem keeps occurring, I would definitely try doing the memory test I mentioned. If that comes up clean, you can rule out memory problems, meaning it's probably a motherboard issue. Are there any other motherboards (yours or a friend's) you could test your RAM in? – nhinkle Mar 8 '11 at 6:05
PS, once you get 15 reputation points, you can thank users for their answers on your posts or other people's posts by clicking the upvote arrow next to their post. You can also vote up questions, which gives reputation as well. Welcome to Super User! – nhinkle Mar 8 '11 at 6:06
@Ethan has the problem reoccurred or is it working with the full amount of RAM now? – nhinkle Mar 15 '11 at 1:31
thanks for the follow up. I finally booted from memtest, which I had trouble mounting to disc at first. It shows 16 GB of memory cached. I increased DRAm voltage out of another recommendation on Toms Hardware to 1.6. but problem persists. May try to clean contacts but it looks like motherboard issue. Maybe update bios? – Ethan Mar 20 '11 at 15:23

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