Windows 7 – Why does my sytem only uses 3.2GB of my 4GM RAM?

I am using win 7 64 bit.

I tried the solution given here, didn’t help.  David’s answer makes me think this is futile.  Is there anything else to try?

Updates:

Notice that I have a graphic card on my motherboard (with 512MB), so in theory, it doesn’t need any external memory.  Also, notice the BIOS latest update (03/25/08).

From what I can see here, there is a newer version (2008/07/30), but I am scared to use it (since it is “BETA”)

Thoughts ?

 Motherboard:     CPU Type   DualCore Intel Pentium D 915, 2800 MHz (14 x 200)     Motherboard Name   Gigabyte GA-945GCM-S2C (2 PCI, 1 PCI-E x1, 1 PCI-E x16, 2 DDR2 DIMM, Audio, Video, LAN)     Motherboard Chipset   Intel Lakeport-G i945GC     System Memory   3328 MB (DDR2-667 DDR2 SDRAM)     DIMM1: 2048736750L   2 GB DDR2-667 DDR2 SDRAM (5-5-5-15 @ 333 MHz) (4-4-4-12 @ 266 MHz) (3-3-3-9 @ 200 MHz)     DIMM3: 2048736750L   2 GB DDR2-667 DDR2 SDRAM (5-5-5-15 @ 333 MHz) (4-4-4-12 @ 266 MHz) (3-3-3-9 @ 200 MHz)     BIOS Type   Award Modular (03/25/08)     Communication Port   Communications Port (COM1)     Communication Port   Printer Port (LPT1)  Display:     Video Adapter   NVIDIA GeForce 8500 GT (512 MB)     Video Adapter   NVIDIA GeForce 8500 GT (512 MB)     3D Accelerator   nVIDIA GeForce 8500 GT   DMI:     DMI BIOS Vendor   Award Software International, Inc.     DMI BIOS Version   F5     DMI System Manufacturer   Gigabyte Technology Co., Ltd.     DMI System Product   945GCM-S2C     DMI System Version       DMI System Serial Number       DMI System UUID   00000000-00000000-0000001F-D06D37BD     DMI Motherboard Manufacturer   Gigabyte Technology Co., Ltd.     DMI Motherboard Product   945GCM-S2C     DMI Motherboard Version   x.x     DMI Motherboard Serial Number       DMI Chassis Manufacturer   Gigabyte Technology Co., Ltd.     DMI Chassis Version       DMI Chassis Serial Number       DMI Chassis Asset Tag       DMI Chassis Type   Desktop Case     DMI Total / Free Memory Sockets   2 / 0  

Solution:

It’s your motherboard that’s limiting the available RAM (more precisely it’s the Intel 945G chipset).

From Gigabyte:

 

Memory

   

     

  1. 2 x 1.8V DDR2 DIMM sockets supporting up to 4 GB of system memory

  2.  

  3. Dual channel memory architecture

  4.  

  5. Support for DDR2 667/533/400 MHz memory modules (Go to GIGABYTE’s  website for the latest memory support  list.)

  6.  

   

* Due to standard PC architecture, a certain amount of memory is reserved  for system usage and therefore the  actual memory size is less than the  stated amount.

What I’m about to put here is based on personal discussions with Intel technicians about this issue:

Since the chipset can only access 4GB of RAM at most, and you have 4GB installed, the chipset statically maps the I/O devices instead of dynamically mapping them (as it’s faster to have it mapped statically).  This makes these RAM addresses invisible to the OS, as it’s never going to be available.

When the system has less than 4GB installed the chipset dynamically maps the I/O instead, so that it can ensure the most amount of installed RAM is available at any time.

To do this, they need to make all the installed RAM visible to the OS so that it can access any potentially available RAM addresses, regardless of where the I/O is mapped at that point in time.   

Since the chipset has to keep track of where the I/O is mapped dynamically, this is slightly slower.

This was a decision made by the Intel design team to ensure top overall ‘performance’ in both fully populated and partially populated configurations.

To get ‘all you RAM’ visible, you’ll need to find a motherboard with a chipset that supports your 64-bit CPU, and allows more than 4GB of RAM.  

Something with an Intel G965 chipset would probably be your best bet.  Perhaps the Intel DQ965GF, we used a ton of these and it was a good board.  It’s slightly outdated these days, but probably still available (as probably are other makes and models with the G965 chipset).

Hope that helps…