When will people learn that you cannot make "amount of VRAM used" a test for how much VRAM is needed for optimum performance? Games fill up more vram than they need...
Now in fairness, it does look like 8xMSAA requires more than 2GB vram at that resolution in FC3, but it's irrelevant as none of these setups are playable at that resolution:
Just because older games don't saturate the available vram doesn't mean that a bottleneck isn't a possibility in newer games. I was showing the utilization of ram for a popular (albeit aged) game. Regardless of whether FC3 is playable at those settings, the bottleneck for the SLI setups was the ram and this trend is likely to continue with newer titles.