i had problems with crysis on my new system witn gtx480, but after a lot of mucking around i found that it had nothing to do with the 480s. it was my bios settings for overclocking the cpu and ram. i found that crysis above all other games is very sensitive to small errors in cpu calculation or memory errors. i found using occt and "intel burn test" very useful.
i think if you run intel burn test on high setting and it fails the test then this would be equivelent to crysis having problems like crashing or abnormal graphics.
you can also test graphics with occt but i think it would stress the cards. also heating would be a major issue. use msi afterburner and see what your temps on gtx480 are . or check cpu temps with coretemp. if you have inadaquit ventilation or cooling in your case you will get faulty data and crashes in crysis. alo check you have just enough voltage for your oc settings not too much voltage. i ran tests for my cpu on high with intel burn test. now i play crysis with no crashes at all. used to play up before.
i have a liquid cooling system for my cpu (hardware labs SR1 RAD 120mm attached to a stock thermaltake inbay system that came with the case and a heatkiller v3 with icdiamond7 thermal paste) i am running my cpu at 4.62GHz crysis stable and intel burn test stable on high setting. above that it fails tests. but good enough for crysis.