Dangerous oc use stock cooling, your system need higher psu for x2 5850.., ueach problem bottleneck,
Minimum oc your cpu at 3.7ghz and gpu still default,
I think use single card and little oc cpu better for you
Yes, grab a water cooler turn off hyper-threading, set multiplier at 20 and get the CPU up to about 3.6Ghz -- 3.8Ghz then hook up crossfire with the 5850s they perform almost as good as a 5870 that is if they work right and the games use them.
I just got a sweet water cooling system for 130.00
Have you tried the bios mod for 5850 ?check out mines