I did my prime check for few hours, it was stable and without any problems, I don't see a point of running it for 24h. I've been running this system with an occasional restarts for weeks now. It runs multiple Lineage 2 clients + whatever I do in the mean time from watching HD movies, playing civilization 5, to running structural engineering calculations (which is what I do for living). The system runs also 2 screens, 24'' and 46'' both at 1920 x1080. I got my H50 pretty much as soon as they became available and yes, I admit I would not use it for some extreme overclocking (benchmarking or w/e - personally i am not into these things), but for the regular use it's just fine, does the job and in the mean time - looks good. I don't want you guys to get me wrong, Noctua is a better cooler and I never said different, but it does look for me like people and please don't take an offense are a bit close minded.