I have a Radeon HD 5970, which, from what I understand is a dual core GPU with each core having access to 2048 MB of vram. I've had some trouble when playing games with the screen briefly freezing up, and so I recently installed performance monitor for skyrim to see if I could pin it down on something, and I noticed that skyrim seems to only be using right under 2000 MBs of vram, is there some reason it doesn't have access to the other 2000 mbs? And is there any way to give it access to them?
In dual GPU set ups, the RAM is shared because the information has to be duplicated across each card. So, if you had 2 cards in SLI, and each has 2GB of VRAM, then you only have access to 2GB of VRAM total, not 4GB.