Two NVIDIA GTX 690's, ASUS Z77 with an i3770K - running MS FSX on surround setup on 3 monitors, all graphics maxxed out in 5940 X 1080 in complex rendering areas sometimes I can drop to around 11 FPS. This sound low for 2 GTX 690 cards? On Average I would say it is running around 30 "ish" FPS, low complex areas I am back up to around 50 FPS.
I know they are the flagship cards, and I know they are the best you can get, but they aren't always the best option. Mainly, they are for benchmarking and for show. Most games have terrible quad-SLI scaling and cannot use the cards to the ful potential.
There's also power issues as well as microstuttering and such, as the drivers have not been perfected.