Windows 7 Ultimate [64bits] - 12GB installed but 3,18GB usable

Question

I've got a Packard Bell iXtreme M5800 and I've added two new memory sticks (2x4G) to upgrade the RAM from 4G to 12G.

The new memory stick are the same type of the old sticks (DDR3-1333) and the BIOS POST displays that 12GB are installed.

But unfortunately Windows detects well the 12GB but it uses only 3,18GB of them...

So I've obviously googled about this issue and done the following:

• do a memory check => no problems were detected
• uncheck the Windows maximum memory limits (Run > msconfig > Boot tab > advanced option)
• update to the new version of BIOS firmware P01-A4 (we never know)
• test different combinations of BIOS parameters options between Memory remap feature, Spread spectrum and clock over all dimm/pci/pcie.
  • Only the combination of clock & spectrum enabled and the remap disable works; the other combinations produce BSOD...
  • when I enable the remap, Windows start fails --> BSOD irql-not-less-or-equal (0x000000A)

As I've read, to allow Windows to use all the memory, the BIOS memory remap parameter should be enabled...

If you have any ideas, you are welcome ;-)

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Here the CPU-Z version (1.71.1.x64) output:

**DMI BIOS**    
vendor          American Megatrends Inc.
version         P01-A4
date            02/15/2011
ROM size        1024 KB

**DMI System Information**
manufacturer        Packard Bell
product         ixtreme M5800
version         unknown
serial          PTU5CE23860400511B2700
UUID            {F9FC8744-DBEC-1020-1009-180525000000}
SKU         To Be Filled By O.E.M.
family          Packard Bell Desktop

**DMI Memory Device**
designation     DIMM0
format          DIMM
type            unknown
total width     64 bits
data width      64 bits
size            2048 MBytes

**DMI Memory Device**
designation     DIMM1
format          DIMM
type            unknown
total width     64 bits
data width      64 bits
size            2048 MBytes

**DMI Memory Device**
designation     DIMM2
format          DIMM
type            unknown
total width     64 bits
data width      64 bits
size            4096 MBytes

**DMI Memory Device**
designation     DIMM3
format          DIMM
type            unknown
total width     64 bits
data width      64 bits
size            4096 MBytes

**DIMM 1**
SMBus address       0x50
Memory type     DDR3
Module format       UDIMM
Manufacturer (ID)    (7F7F7F7F7F7F7F070000)
Size            2048 MBytes
Max bandwidth       PC3-10700 (667 MHz)
Part number     GU512303EP0202
Manufacturing date  Week 32/Year 10
Number of banks     8
Nominal Voltage     1.50 Volts

**DIMM 2**
SMBus address       0x51
Memory type     DDR3
Module format       UDIMM
Manufacturer (ID)   Kingston (7F980000000000000000)
Size            4096 MBytes
Max bandwidth       PC3-10700 (667 MHz)
Part number     9905402-664.A00LF 
Serial number       653E387A
Manufacturing date  Week 44/Year 14
Number of banks     8
Nominal Voltage     1.50 Volts

**DIMM 3**
SMBus address       0x52
Memory type     DDR3
Module format       UDIMM
Manufacturer (ID)    (7F7F7F7F7F7F7F070000)
Size            2048 MBytes
Max bandwidth       PC3-10700 (667 MHz)
Part number     GU512303EP0202
Manufacturing date  Week 32/Year 10
Number of banks     8
Nominal Voltage     1.50 Volts

**DIMM 4**
SMBus address       0x53
Memory type     DDR3
Module format       UDIMM
Manufacturer (ID)   Kingston (7F980000000000000000)
Size            4096 MBytes
Max bandwidth       PC3-10700 (667 MHz)
Part number     9905402-664.A00LF 
Serial number       6E3E1B7A
Manufacturing date  Week 44/Year 14
Number of banks     8

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Update

To avoid misunderstanding regarding some comments, it's a fresh W7-SP1 Ultimate 64bits installation.

Windows Version         Microsoft Windows 7 (6.1) Ultimate Edition 64-bit  Service Pack 1 (Build 7601)

Answer 1

Why is usable memory different to physical memory?

The physical memory limit depends on which version of Windows you have. However the usable memory (which may be less than the installed memory) depends on other factors.

You have Windows 7 Ultimate (64 bit). According to the table below the maximum physical memory is 192 GB.

However, all of this memory may not be usable (see below).

Source Physical Memory Limits: Windows 7

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On a computer that is running Windows 7, the usable memory (RAM) may be less than the installed memory

The reduction in available system memory depends on the configuration of the following:

• The devices that are installed in the computer and the memory that is reserved by those devices
• The ability of the motherboard to handle memory
• The System BIOS version and settings
• The version of Windows 7 that is installed (For example, Windows 7 Starter Edition only supports 2 GB of installed memory.)
• Other system settings

If you have a video card that has 256 MB of on-board memory, that memory must be mapped within the first 4 GB of address space. If 4 GB of system memory is already installed, part of that address space must be reserved by the graphics memory mapping. Graphics memory mapping overwrites a part of the system memory. These conditions reduce the total amount of system memory that is available to the operating system.

...

Check BIOS settings

The problem may occur because some BIOS settings are incorrect.

Enable the memory remapping feature

Check the BIOS settings to see whether the memory remapping feature is enabled. Memory remapping gives Windows access to more memory. You can enable the memory remapping feature in the BIOS by booting to the system setup. See the User's Guide for your computer for instructions on how to boot to system setup on your computer. The name for the memory remapping feature may be different for different hardware vendors. This can be listed as memory remapping, memory extension, or something similar. Be aware that your computer may not support the memory remapping feature.

Change the AGP video aperture size in the BIOS settings

Check the BIOS settings to see how much memory that you have allocated to AGP video aperture. This is the memory that the system is sharing with the video card that is used for texture mapping and rendering. This memory would not be used by the system, because it is locked by the video card. You can adjust the AGP video aperture size in the BIOS. Standard settings are "32MB,""64MB,""128MB,"and "Auto." After you change this setting in the BIOS, restart your computer, and then check the usable memory. You can test each setting to see which offers the best results.

Source The usable memory may be less than the installed memory on Windows 7-based computers

Answer 2

Memory remap should be enabled in BIOS. You have to remove the cause of BSOD and enable it. This issue isn't uncommon, but no universal remedy is known. Here is some voodoo that may help:

• Reset BIOS to defaults and boot.

• Download CCleaner and run Registry scan, then Fix all.

• Download latest chipset drivers.

  Downloads on Packard Bell's site are quite dated (Q2 2010), so you'll have to head to Intel's website. Identifying correct driver on their website is a painful process, but I guess you can use the Update Drivers button or try this category: Software → Chipset software → Intel Chipset Software Installation Utility.

• Download your antivirus. (Unless it's AVG, in this case try something else - for example Microsoft Security Essentials. Not that I don't like AVG or something, removing AVG is simply part of the voodoo...)

• Uninstall antivirus. Reboot.

• Uninstall chipset drivers. Reboot. Run CCleaner's registry fix again.

• Enable memory remap in BIOS. Try to boot - hopefully it will work this time.

• Install latest chipset drivers. (You should have downloaded them earlier.) Reboot.

• BSOD? Disable memory remap, boot, uninstall drivers, reboot, reinstall drivers, reboot, enable memory remap, boot.

• Reinstall antivirus. Reboot.

If these steps don't help, try to reinstall Windows, but this time make sure memory remap is enabled during installation.

Answer 3

From your CPU-Z report, you have memory slots 0 and 1 (DIMM1 and DIMM2) filled with a pair and slots 2 and 3 (DIMM3 and DIMM4) filled with a pair.

It appears that the memory is installed incorrectly, though I am unsure why the BIOS would report the amounts properly.

DIMM slots are matched odd/even and usually motherboard slots are color coded. So pair 1 should be in slots 0 and 2 (cpu-z calls these DIMM1 and DIMM3) and pair 2 should be in slots 1 and 3 (DIMM2 and DIMM4).

I checked my own computer just now with cpu-z and the report conforms to this.