[Heartsbane]

I have a Core 2 Quad with 2x2GB of RAM (4GB Total). I'm using Windows Vista Ultimate (32-bit). When I go to Computer Properties, It says "Memory (RAM): 4.00 GB" -- so it's recognizing all of the RAM there. However, when I go to Task Manager Performance tab, it says I have 1533 MB of Physical Memory (less than 1/2)!!!

I also have Windows Virtual Server 2005 on this machine, and when I go to server properties it is *also* reporting only 1533 MB of RAM!

I'm inclined to believe that Vista is only using 1533 MB of my 4GB of RAM because Task Manager constantly shows my Physical Memory usage at 85% and higher.

Anyone seen this or have any idea how I can get Vista to recognize/use all of my 4GB of RAM?!?

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What Video card have you got?

As the amout of RAM a video card has is mapped before your other RAM and its to do with 32bit OS and no extra memory mapping

Soory the answers a bit vaig

SpuD

[==SpuD==]

What Video card have you got?

As the amout of RAM a video card has is mapped before your other RAM and its to do with 32bit OS and no extra memory mapping

Soory the answers a bit vaig

SpuD

[Makaveli213]

32 Bit has limitations. The first and largest Limitation is the 4GB limit. Meaning that 32 Bit can not and will not recognize or utilize 4GB of RAM. The Max you will get is 3.5GB of RAM recognized and utilized on a 32 Bit system. No before anyone goes off on me for the fact that Vista SP1 will show that you have 4GB installed you still do not get to utilize that 4GB as it will not use that other 512MB.

In order to access Address X, the CPU needs to store the value of X in a register in the CPU and tell the memory to read the contents of the address stored in that register.

Registers in x86 PCs are limited to 32 bits, which means the biggest number that can be stored in that register is 2^32, or 4,294,967,296; which means that the CPU can access up to "ADDRESS 4,294,967,296" which is the 4th GB of data.

The problem is that the CPU also access I/O devices (printer, USB, keyboard, mouse, monitor, etc.) by assigning them an address as well. So it reserves half a GB or so of the memory addresses to talk to the I/O devices... So you have 4GB - ~0.5GB -> 3.5 GB (on Windows it is 3.2GB).

This is the only reason x64 was invented.

I hope this better explains why 32 Bit will never be able to see or use 4GB of RAM. Also taking into account that your Video card's memory is also tallied into the equation as mentioned above. So take away the Video Memory and hte 80MB already taken out from Windows and you have your answer.

Cheers,
Mak

[Heartsbane]

Thanks for the replies! I understand the 4GB of *total* address space on 32-bit, including the 512MB reserved by the OS for devices. In addition, I'm running 2x512MB nVidia 8600 graphics cards in SLI, so I'm guessing that uses up another 1GB of the 4GB. That takes me down to 2.5GB, but I'm still only seeing 1.5GB. There must be other devices in my system that are using up more of this address space. My system also has 5 hard drives -- 1 for OS and a 4x1TB RAID 0 for data/storage.

I've read about using PAE to allow more than 4GB of RAM on 32-bit Vista:

http://www.microsoft...PAE/PAEmem.mspx

But I'm not sure this would solve the problem or if it's just an unreliable band-aid.

I originally tried 64-bit Windows Vista, but it seemed to be flakey -- especially the nVidia 64-bit SLI video driver. Looks like I might have to give it another try -- maybe the drivers have gotten better...

[Makaveli213]

Hello,

Sadly from all the talks i have heard of PAE and Vista 32 Bit it will just be a bandaid that is not worth it. Vista 64 Bit will be the answer as it has gotten a bit better.

Cheers,
Mak