Windows 7 64bit - only 3.2gb RAM available

garlik_bread

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System:

Pentium D 945 3.4ghz
Intel D945GTP Motherboard
4 GB DDR2 (4x1gb)
ATI HD 3650 512mb PCIE Graphics

Even though W7 64bit is installed and runs fine, shows up as 3.2gb memory available. I think it is because the BIOS is quite heavily locked by OEM.

Would the make any difference if i were to remove a stick of RAM, taking it to 3gb? As the 512 MB gfx card will be addressing part of the 3.2gb available?
 
If you remove some RAM, you'll just have less memory!

The problem is you have an old motherboard. You might be able to get a BIOS upgrade to improve 64-bit memory addressing.
 
If you remove some RAM, you'll just have less memory!

The problem is you have an old motherboard. You might be able to get a BIOS upgrade to improve 64-bit memory addressing.

Is it the case though that the BIOS is restricting the overall adressable memory to 3.2GB (incl. RAM, GFX etc.). Taking into account that the GFX card has 512mb, where does that fit into the equasion? Is a portion of the adressable memory reserved for the graphics?

Therefore, if i reduced to say 2.5GB RAM, there would be enough left over for the 512MB GFX. I think this woulkd be the case for 32bit, but as this is 64bit does it work differently?

As for upgrading the BIOS, tried before but none of the updates will work due to it being a manufacturer BIOS on an Intel reference board.
 
As i understand it, the motherboard itself can only support 4gb maximum (whereas i thought it was 8gb). Therefore, other devices are getting reserved address space before the RAM is mapped, leaving only 3.2gb.

2.2.1 Addressable Memory
The board utilizes 4 GB of addressable system memory. Typically the address space that is allocated for PCI Conventional bus add-in cards, PCI Express configuration space, BIOS (SPI Flash), and chipset overhead resides above the top of DRAM (total system memory). On a system that has 4 GB of system memory installed, it is not possible to use all of the installed memory due to system address space being allocated for other system critical functions. These functions include
the following:
• BIOS/ SPI Flash (2 MB)
• Local APIC (19 MB)
• Digital Media Interface (40 MB)
• Front side bus interrupts (17 MB)
• PCI Express configuration space (256 MB)

Intel Desktop Board D945GTP Technical Product Specification
• MCH base address registers, internal graphics ranges, PCI Express ports (up to 512 MB)
• Memory-mapped I/O that is dynamically allocated for PCI Conventional and PCI Express add-in cards
The amount of installed memory that can be used will vary based on add-in cards and BIOS settings. Figure 17 shows a schematic of the system memory map. All installed system memory can be used when there is no overlap of system addresses.​

So, if i were to reduce the amount of Physical RAM to 3gb i would only be wasting 0.2gb. Or i could swap out the 512mb GFX card with a 256MB one, and would be able to see address 3.5gb RAM
 
So, if i were to reduce the amount of Physical RAM to 3gb i would only be wasting 0.2gb. Or i could swap out the 512mb GFX card with a 256MB one, and would be able to see address 3.5gb RAM
If you have other PCs you can use the RAM in, fine.
 
If you have other PCs you can use the RAM in, fine.

Yeah, my sisters PC could do with some more. Infact, i would have to remove a 256 stick from hers to fit the extra 1gb...So i could then have have 3.2gb physical in my machine, albeit not dual channel. :facepalm:
 
Ended up removing the 1gb and putting it in my sisters machine. Both are running fine, no noticeable difference in my machine with the less RAM other than windows score gone from 5.3 to 5.0.
 

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