Trust me, I know.
I have spent nearly a FULL DAY tweaking the video settings on my rig, and its easily twice or more as powerful as yours. The best I can manage is around 15-30fps despite using every optimizer and graphic config I can find. The mod is not currently optimized as its in BETA form, the maps are somewhat ludicrous in scope, and the net code is particularly brutal. But all mods have growing pains.
What I CAN suggest is googling "CCC Crysis 1.31" and following the autoexec instructions, setting sound quality to low or medium, and just accepting that this mod pretty much rapes most computers. Also there appears to be a handful of us that just get shafted for whatever reason, time will tell if its resolved I guess.