that is one of the best air coolers out there together with a NH-D14 from noctua.
how high you can get the clocks depends allot on how good your chip is. Best is to test how far you can push core clocks stable with stock Vcore after that you just need to add tiny amounts of voltage to reach the next region of clocks. (iirc wow OC performance sweetspot was around 4.4/45 Ghz)
prepare for a healthy dose of info here ;
http://www.overclock.net/t/1247413/i...ide-at-the-end (ofc you can skip the LN2 part hehe)