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My computer says only 7.90GB of 8GB is usable. What is preventing it from using all 8GB?

Anonymous
2012-06-14T20:00:23+00:00

original title: My PC stopped accessing all my RAM

Hello all

PC: OS: Windows 7 Enterprise SP1, 64-bit,  processor: Core i7-2720QM, RAM: 8Gb

Problem: for the last two days, every time i check computer properties it says: 8.00 Gb (7.90 Gb usable). I re-assessed my computer performance but nothing changed.

Question: why cannot my PC use all the 8Gb of ram??? any ideas or help please.

Win7-Geek

Windows for home | Previous Windows versions | Windows update

Locked Question. This question was migrated from the Microsoft Support Community. You can vote on whether it's helpful, but you can't add comments or replies or follow the question.

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  1. Anonymous
    2012-06-15T01:46:38+00:00

    It's not a problem for the fourth time now in the thread and I just got done telling you that you created the "problem" by actually updating the bios.

    For the third time now, you may contact the manufacturers to have them help you learn about the "problem".

    Is there anything else we can do for you today?

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  1. Anonymous
    2012-06-15T01:38:04+00:00

    BIOS updates can be quite malignant sometimes

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  2. LemP 74,925 Reputation points Volunteer Moderator
    2012-06-14T20:49:05+00:00

    This is normal.  The operating system (e.g., Windows 7) has a defined "address space" that limits the amount of memory it can access.  For 32-bit operating systems (e.g., Windows XP), that limit is 4 GB.   For 64 bit operating systems (e.g., some versions of Windows 7) it is 192 GB.

    That said, however, Windows uses some of that address space to communicate with various hardw2are devices installed in the computer.  The biggest user in this category is your video card. 

    Because of the hardware reservation, many Windows XP users were surprised to find that when they installed 4 GB of physical RAM in their computers that Windows reported only about 3.3 GB of usable memory.

    The same thing is happening to you.  In your case, because you have a 64-bit version of Win 7, Windows has a very large address space .... but it still needs some of those addresses to communicate with your hardware.  In your particular case, that's only about 100 MB.

    If you click on "Resource Monitor on the "Performance" tab of Task Manager and then select the "memory" tab, you'll see the "Hardware Reserved" section at the left end of the graph.  The sum of" Hardware Reserved" and  "total" should equal "installed."

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  3. Anonymous
    2012-06-14T20:33:42+00:00

    but this is 64-bit system. RAM in theory should be shared by all components and not reserved to some hardware like the situation is in 32-bit systems.

    however, How can I know what hardware is reserving that memory. as i said, this is a very recent issue and I am using a laptop, so there are no additions to the machine in terms of hardware.

    many thanks

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  4. Anonymous
    2012-06-14T20:26:19+00:00

    As to be expected, hardware resources are using some ram

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