I saw bunch of articles and videos where people overclocked little bit with stock cooler. a friend also told me that it is kinda safe since im not going for big overclock .
Last night i overclocked it to 4GHz by raising multiplier to 20 and turning off turbo. I run prime95 for 1h 6m and with no errors temp was constant at 62C (59C if i manually set fan to 100%). I also ran AMD Overdrive for 1 hour and temp was 56C. Tried for 10+ minutes 4 games (Bioshock Infinite, Skyrim, Tomb Raider and Startcraft II Heart of the Swarm) and temp was about 45C. As war as i can see those are not too high temps. In idle temp is really low since CPU speed drops to 1.4GHz