I've been using a stock intel i5 heatsink for the past year and have noticed an increase in fan noise over the year. I think now is the time to upgrade to a better cpu cooler, but I need help picking the right kind. I don't care if it's water cooling or if its a regular kind as long as it's quiet.
Noctua and Bequiet branded one are very quiet, i mean VERY quiet... If you're not in the need for a really silent PC (if you can tolerate some noise even if it's barely audible) i suggest you the CM 212 evo for about 30$, it'll cool the cpu very well and it's almost silent (fan isn't a Noctua one but still fairly silent comparing to other branded fans like the Corsair ones)