Quote Originally Posted by NaMcO View Post
What does video memory have to do with the OS?

Do you have to run a 64-bit OS in order to have 4GB video memory? I don't think so, could be wrong though. Besides that, each GPU is fed 2GB not 4.
What are you talking about? It does not matter if the memory belongs to 1, 2 or 50 GPU cores. OS adresses WHOLE memory in the computer. That means RAM, VRAM, CPU L1, L2 and L3 cache, HDD cache etc. OS x86-32=2^32=4 GB. You won't be able even to boot the system up since RAM is last in the line to be adressed.