I've been seeing a lot of people using AIDA64 to verify stability of overclocks. The "stress test" included is not good at generating heat nor is it effective at identifying computational errors. AIDA64's stress test will run for hours on overclocks that will BSOD while browsing the internet. The purpose of stress testing is not to place an unrealistically low load on your CPU just so you can pass - it is to subject your CPU to the most extreme thermal and computational loads possible in order to verify that, in regular use, instability is not a concern. Prime95 SmallFFTs is excellent for identifying core instability and thermal limits for overclocks. ASUS RealBench is not very stressful on thermals, but it does generally find stability issues relatively quickly.