I play on Ultra with 3x580 3gb and it eats about 2gb VRAM. Frames go anywhere from 40 - 120 during multi-player, using adaptive vsync now to keep it a little more stable.
Have a Asrock Gen7 MB and it has a space between each pcie lane so my cards arent sandwiched together, temps max out at 71degrees on the hottest card (bottom one strangely enough), slightly overclocked core @850
playing at 5870x1080p 60hz.
I would say because you have the 3gb version, its not VRAM, Probably a cpu bottleneck as 64 player online is a cpu hog.
Awesome, this is exactly what I was hoping to see. With my 2 680GTX with 4 gig each plan should be able to handle it maxed out. I'm waiting for the classified version with hydro copper as I want to water cool it. The FTW versions are non-reference so existing waterblocks won't work. :((
As stated, my 590 is 3GB combined, so 1.5 each. Not sure what would be causing the fps drop, but it only happens on "large" maps after playing for a long time.