Ahh, pleahhhse. What are you playing, chess and WoW, perhaps even ETQW? FYI playing at 30-40fps is NOT gaming, that's struggling - you have to hit around 50-60fps on average to make sure it doesn't dip below 30 too many times.
My 4850 x2 2GB - quite a bit faster than your SLI, mind you - can handle everything but not at full blast, you have no idea what are you talking about if you really believe this.
Forget Crysis, this lame crap engine - try playing STALKER: Clear Sky everything maxed out in 1920x1200 or try World in Conflict maxed out in a nice, massive scene or something modern, demanding stuff. Your 8800GT SLI will struggle, I bet.
BTW unless you use a CRT switching to lower resolution gives you the worst picture quality you can get, thanks to cheap scalers in flat panels.