what are you doing exactly? Playing a game or nothing? If you're on a laptop and it's on a desk, put it on your lap because the computer is overheating.
I'm not sure but the fan might be outdated, is it? To know this is also important.
I don't think it's anything to worry about, a lot of laptops do this.
dude just stop, you obviously have no idea what you are talking about
i also have the Hyper 212 Evo. one day it also just randomly started to go to max RPM. if you cannot adjust your fan speed through BIOS (which, for some reason, I could not with an MSI AM3+ motherboard (its like FX970-G46 or G43 or something along those lines)), another option which I used is to download speedfan and manually adjust it through that.