Does Windows 7 really give a performance boost over Windows Vista?

[Sam DeathWalker]

2x nVidia Geforce 8800GTS (684Mb video ram) in SLi mode

2 X 684 is about 1.5 G ..... what else do you expect?'



have found somewhere on the net that windows and/or the bios will assign a big chunk of your main ram to cover as interface between the video ram and the rest of the computer.

This is correct.

[BobGnarly]

2x nVidia Geforce 8800GTS (684Mb video ram) in SLi mode

2 X 684 is about 1.5 G ..... what else do you expect?'



have found somewhere on the net that windows and/or the bios will assign a big chunk of your main ram to cover as interface between the video ram and the rest of the computer.

This is correct.

It is correct for 32-bit OSs, it is NOT correct for 64-bit OSs (or at least it doesn't have to be).

The problem is that, in a 32-bit OS, it can only address 4G of memory (2^32) total. That means for things like video cards, the MMIO for these devices must lie withing that 4G range. Since you have 4G of RAM, there is nowhere left for the MMIO to exist except over the top of your RAM, meaning you lose the memory.

On a a 64-bit OS, it can map the video card memory above your RAM address range - it will not conflict with your RAM.

Short story: if you are running a 64-bit OS, you shouldn't have any peripheral I/O memory subtracted from your usable RAM total. If you do, something is misconfigured (probably your m/b).