I have been messing with SLI and surround, and just some quick information about memory usage on BF3 and Crysis2--as I have been a little concerned about this. I only did about 10 minutes of testing each, so please keep that in mind.
I am running two 680s @ 5760x1080, clocks are boosting to 1200 - 1215 mhz.
BF3: All settings on Ultra, blur turned off, MSAA x2 is showing about 1.8GB of memory usage. I have vsync enabled, and it is holding a strong, steady 60fps. When I max out the MSAA at x4, framerates hold at the 60hz refresh rates until the memory maxes out (after a minute or two), and it then drops into the 50s. x2 MSAA is fine, but once you up it to x4 MSAA the cards start to run out of memory at that resolution. These quick tests were done in a multiplayer match with about 24 or so people in it.
Crysis 2: In single player with all settings on Extreme, blur turned off, and vsync enabled, the cards are showing about 1.6 GB of memory usage and hold 60 fps quite solidly. When the settings are turned up to Ultra the fps drops considerably and varies anywhere from 30fp - 60fps, with about 1650MB of memory usage. I definitely wouldn't recommend playing on Ultra, it's quite choppy at times, and certainly not what I would consider playable. But Extreme is certainly smooth. I am not using the Dx11 or high res packs.
Just though I would share this since I noticed I was running out of vram in BF3 @ x4 MSAA and it was dropping my fps.
Also, it is worth noting that I haven't tweaked the profiles yet, these are just results with the vanilla global profile.
Okay, got some more information. This time I ran BF3 on Gulf of Oman with about 50+ players to get more hard hitting results. All settings are on Ultra, motion blur disabled, and MSAA x2. Here is a screen of the afterburner hardware monitor. I tried to organize it so that I could fit in the main items of importance without too much clutter:
Honestly, I would turn down the settings a tad if I were to play on servers that busy as the fps was bouncing around below 60 too much for my liking. Also, as you can see, it was using a bit more vram too.
On another note, I am utterly shocked at how smooth SLI is, it very much feels just as smooth as a single card. I am impressed.Edited by svthomas - 4/17/12 at 12:30am