6Gb Memory (3.99 Usable)

What does it mean when Windows tells me 6Gb Memory (3.99 Usable)?

Windows 7 Home Premium 64-Bit

Difference is shared memory with video card in some instances. Bios update has slight chance of making it use all.

Microsoft said:

(Note: in the following info from Microsoft, replace "4 GB" with "6 GB" since that is how much RAM you have. Replace "Windows Vista" with "Windows 7")

For Windows Vista to use all 4 GB of memory on a computer that has 4 GB of memory installed, the computer must meet the following requirements:

• The chipset must support at least 8 GB of address space. Chipsets that have this capability include the following:
  
  • Intel 975X
  • Intel P965
  • Intel 955X on Socket 775
  • Chipsets that support AMD processors that use socket F, socket 940, socket 939, or socket AM2. These chipsets include any AMD socket and CPU combination in which the memory controller resides in the CPU.
  
  
• The CPU must support the x64 instruction set. The AMD64 CPU and the Intel EM64T CPU support this instruction set.
• The BIOS must support the memory remapping feature. The memory remapping feature allows for the segment of system memory that was previously overwritten by the Peripheral Component Interconnect (PCI) configuration space to be remapped above the 4 GB address line. This feature must be enabled in the BIOS configuration utility on the computer. View your computer product documentation for instructions that explain how to enable this feature. Many consumer-oriented computers may not support the memory remapping feature. No standard terminology is used in documentation or in BIOS configuration utilities for this feature. Therefore, you may have to read the descriptions of the various BIOS configuration settings that are available to determine whether any of the settings enable the memory remapping feature.
• An x64 (64-bit) version of Windows Vista must be used.

Contact the computer vendor to determine whether your computer meets these requirements.

Note 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.

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

sup3rsprt: I love you man!!

Much love, iluvatar2001

But seriously! This problem has been giving me I headache since I installed Vista Sp1. And trough win7rc and win7pro.
Because of your post I realized that my motherboard is crap, and I have to buy one that supports more than 4GB ram.

Finally I can put it to rest.

I'd still give a look over in the bios for a Memory Hole or Memory Remap option. If you find either one make sure it is enabled as they are disabled by default on most. Also having the latest bios is always a good idea

Zahl said:

I'd still give a look over in the bios for a Memory Hole or Memory Remap option. If you find either one make sure it is enabled as they are disabled by default on most. Also having the latest bios is always a good idea

I'm in the same boat (have 4GB memory but only have use of 3GB of memory). When I enable memory mapping in the bios
I can then see and have access to the full 4GB of memory but then my system will hang at shut down and WON'T shut down. I have to disable memory mapping in order to shut down my system. I have the latest bios.
Using win7 64 with a ASUS P5B premium series motherboard.

FyrmnJ