When running SLi in Crysis and Crysis Warhead performance is terrible. If I disable SLi performance is alot better. However i've just spent £1600,00 on a new build and was expecting to play Crysis at around 40 - 50 fps @1680 x 1050. All other games run like a dream i.e COD 4, GTA4, Dead Space etc
Have you tried alternate frame rendering settings?, also bear in mind that you have four GPU's rather than two and Crysis is badly coded anyway (IMHO) so whilst it runs better with two GPU's it may just be confused when presented with four.
When you say you're running sli, do you mean have two gtx 295 cards or are you just referring to the dual GPU nature of a single gtx 295?
I had the exact same problem a while ago with Crysis [Warhead]. Fraps said I was getting 50, but it in no way felt like 50. It was like the system was operating in sli, but one of the cards just wasn't outputting anything. The culprit turned out to be a corrupted game profile, which is odd because I had never changed it. I used Rivatuner to reset my game profiles and that fixed it.
P.S. r_displayinfo 1 in the console will give you your framerate (along with other details)
ive read many reviews like these, and i did see someone say that actually when you run SLI 295, performance goes down...i dont know the exact reason why, but i do think you'd need to have some extream computer to run SLI 295 at very good performance, possibly 4.5 GHz? im not sure, but ive read reviews that performance does go down
When playing crysis, press the ~ key to open console and type in "r_displayinfo 1" without quotes and it will show you your exact fps as you play. Nothing should be bottlenecking you becuase you have excellent processor/ram/psu. so there must be a problem with either crysis(since you say other games work well) or you gpu....most likely crysis though, however there can also be possibility of faulty hardware so dont forget that. Try reinstalling and basic stuff. Set all low settings and see how it affects you also.
It looks like Crysis is the culprit. I get around 35fps all on Gamer settings with 1 gpu enabled and only 22fps with both gpu's enabled. I did try altering the rendering settings of Crysis but it's made no difference. Just to make sure the card is fine I ran fraps in COD4 , maxed out i'm getting 78 - 85 fps and both gpu's enabled i'm getting 120 -130 fps so it looks like my card is fine at least.
sorry for saying that but no issue with Crysis on 185.85 driver...just checked. I have GTX 295 and only q6600 oced at 3.6 and 1920*1200 is giving me 38fps and 1650*1080 is 41fps. You must have bit more, not too much although your CPU is much more powerful than mine but Crysis is mainly GPU demanding. I assume that i7 920 at 3.6 must push it about 40-41fps at 19*12 and 47-48fps at 16*10. Everything was very high and no aa and no microstuttering at all. Check your drivers, uninstall it properly, use driver sweeper and re-install once again. Check also your Vista whether there is no need for some update. Do some benchmarking in games and check whether your fps are matching those ones published on some websites like tom´s hardware, 3dguru, pcgameshardware etc...
I've just uninstalled Crysis Warhead and deleted any remaining entries from the registry and then installed it back again. It now works fine. However when I switch to single GPU obviously I get alot lower FPS but when I switch back to dual GPU I get the stutterig. If I then re-boot it works fine with both GPU's. I cqan live with that. I'm getting aorund 60fps average maxed out DX10 with 2x AA @ 1680x1050.
Ive got a Core i5 750 @ 4.1 GHz and a GTX 295 with the same problem... GTA 4, TF2, UT3 etc... all runs smooth as a baby's butt! But Crysis lags like hell, I get like 20 fps and it really doesn't matter what settings I have. This is retarded. I got better performance with my old 8800GTX and E6600... WTF!