I think that's at least partially because it seems logical that it would double. Along the lines of other types of computer related memory. Also, I have never really seen a good, technical explanation of why this is the case. Anyone got one? I'm not insinuating that one doesn't exist or it's just a bs business decision but at any rate it's certainly not widespread info and common knowledge.
SLi and Crossfire both act in the same why with memory. The amount of VRAM is not doubled because each GPU needs to be fed with the data in VRAM directly. Since each GPU is working on rendering the same frame* both GPUs need high speed access to the same data, the only thing fast enough to provide that data is the directly link between the memory and the GPU. It would be too slow to have GPU1 accessing data from GPU2's memory, PCI-E and SLi/Crossfire bridges are not fast enough to handle this. So all the data must be duplicated in the VRAM on each card.
*There is the case that Alternate Frame Rendering mode might be used, in this case the two frames are still so close together that the data in VRAM must be virtually identical.
Awesome! Maybe this was prior cards or something; could have sworn saw that from W1z himself at some point. I have tried with my 460 but it didn't seem to be working right...will try further.
It is there, and it works. The older versions of GPU-z didn't have this feature, and I don't beileve it works with some of the older nVidia cards, but it definitely works with the newer 400 series cards.
I'd use this just to make sure the VRAM is the cause. Set it to display the Max memory used(by clicking on the number) and fire up Dirt2. When you are done playing, check GPU-z to see how much it peaked at.
