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I have Windows 7 64 bits Home Premium with 2x4GB Ram, but the system shows only 4.75GB available in Windows.

MrLemon
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user329950
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2 Answers2

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There are tons of questions like this on the internet as well as on this site such as 8.00GB RAM (3.22GB usable) in Windows 7 x64

There are many possible reasons and you need to check each:

  1. The most common problem is that memory mapping is disabled. You need to go to BIOS setup and look for memory remapping or something like that and enable it. If nothing is found, update BIOS to the latest version and recheck.

    See Installed Memory (RAM): 8GB (4GB Useable)

    memory remapping

    If still no entry like that, try the next step

  2. Go to BIOS setup and try reducing or disabling shared RAM for integrated video card (GPU)

  3. Windows+R > type msconfig and press Enter. In tab Boot open Advanced options and check if Maximum memory is being checked. If true, uncheck it

  4. Check if there are any devices taking addresses too much. Disable it or reinstall driver

    See Windows only sees 768 MB RAM out of 4 GB

  5. Take out the memory modules, swap them or plug them into the other pair of slots (if any). This is because those need to be matched in correct slot pair if a multi-channel memory architecture like flex memory is used. Clean the pins if necessary.

If all the other solutions don't work, you may have no luck.

You can read about the reasons and solutions on MS support and MS technet

phuclv
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Create a boot disk using MemTest86+ and use it to diagnose your RAM. You can download an *.iso here: http://www.memtest.org/

Or try booting with stick 1 and see if the system recognizes 4GB, then use stick 2 by itself and see if it recognizes 4GB. Then put one stick in slot 2 and none in slot 1 and see what it recognizes. You want to diagnose each stick and each slot to see if there's a hardware issue.

HighTechGeek
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