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Windows 7: 4GB RAM Installed 3.5GB Usable x64 bit Windows 7

02 Jan 2011   #1

4GB RAM Installed 3.5GB Usable x64 bit Windows 7

I recently built a system with a Gigabyte 880GM-UD2H motherboard with an AMD Phenom II Black Edition processor. I installed 2x2GB Crucial Ballistix Ram cards. While looking at my system properties i noticed I only had 3.5GB of usable ram. If you could please shed some light on this issue it would be great. I am pretty much learning on the go with this computer build so any help would be greatly appreciated.

My System SpecsSystem Spec
03 Jan 2011   #2

Win7 Enterprise, Win7 x86 (Ult 7600), Win7 x64 Ult 7600, TechNet RTM on AMD x64 (2.8Ghz)

Welcome karlmajors

This thread is similar & explains some things. Also could be being used for you video card, too.

Only 2.5 GB available RAM out of 4 GB 64 bit OS
My System SpecsSystem Spec
03 Jan 2011   #3


I read threw that thread and tried doing the config with setting max to zero. System wouldn't boot. After booting in safe mode and reseting that config to 4096, it says i now only have 2.75 GB usable of 4 GB installed. I looked at the resource monitor it says that 1282MB are reserved for hardware? I am not even sure what that means but before i did the system config it only say 512MB was reserved for Hardware.

My System SpecsSystem Spec

03 Jan 2011   #4

Win7 Enterprise, Win7 x86 (Ult 7600), Win7 x64 Ult 7600, TechNet RTM on AMD x64 (2.8Ghz)

What video card do you have & how much memory does it have onboard? Also sometimes there is a place in the Bios setup that does memory re-mapping to allocated memory to different areas.
My System SpecsSystem Spec
03 Jan 2011   #5

Windows 10 64 bit

The 3.5GB sounds "normal". You will never have the full memory available. I have 8GB of RAM and generally have about 6.5 GB available.
My System SpecsSystem Spec
03 Jan 2011   #6
Microsoft MVP

Win 7 Ultimate x64

That is only "normal" when you install the max amount of memory that the motherboard can support. In your case you have 8 GB and that is the max the board supports,

Intel® Desktop Board DP35DP — System memory

and this is why,

The system memory that is reported in the System Information dialog box in Windows Vista is less than you expect if 4 GB of RAM is installed

When the physical RAM that is installed on a computer equals the address space that is supported by the chipset, the total system memory that is available to the operating system is always less than the physical RAM that is installed. For example, consider a computer that has an Intel 975X chipset that supports 8 GB of address space. If you install 8 GB of RAM, the system memory that is available to the operating system will be reduced by the PCI configuration requirements. In this scenario, PCI configuration requirements reduce the memory that is available to the operating system by an amount that is between approximately 200 MB and approximately 1 GB. The reduction depends on the configuration.
Now with that said according to the specs for karlmajors board says up to 16 GB (on all 3 revisions of the board),

GIGABYTE - Motherboard - Socket AM3 - GA-880GM-UD2H (rev. 1.3)

and had a look at the manual for it and there is no re-mapping option in the bios; usually means that it is on by default.

It would help to know whether he is using the onboard video or not. It has four options for the amount of memory to allocate for the onboard; auto, 128 MB, 256 MB and 512 MB, with the default being Auto and the onboard being enabled by default as well. It doesn't say in the manual but it is possible that with 4 GB or ram that the Auto setting is maxing out at 512 MB.

If he is using the onboard 256 MB should be more than enough. If not using it go into the bios and disable it completely.
My System SpecsSystem Spec

 4GB RAM Installed 3.5GB Usable x64 bit Windows 7

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