Stock heat sinks/fans suck. Go to newegg and get a Cooler Master Hyper 212+ for 19.99 should solve the problem. Your graphics card heatsink/fan should be fine, since they arent really made to be replaced they are made with a bit more quality than this crap we get from intel and amd. The hyper 212 seems really big, and it is, but it fit just fine in my challenger case (have about 1/4 inch of room left lol)
Edit: To verify, hook up two monitors and get Core Temp and CPUID or some other heat monitoring program and try and recreate. Just keep a close eye on them temps and you will know if it gets to hot. 60C is a good number when stressing your CPU. My system is still new and not yet "stable" in my eyes so when I play Diablo iii I like to keep an eye on all my monitoring programs.