i know there is alot lot things to do with overcloking, this is my first time and first build pc, very2 noob  but just wanna try, i no nothing about adjusting the voltage, latest eufi or what else, i just using the auto setting overcloking from this mobo on bios, no update nothing, just wanna try, any comment or suggestion are welcome, thanks alot, just wanna know is it normal result, temperature, and can i lower the voltage but constant the ghz?

by the way this is my spec : i72600k @4.8ghz , tuniq tower 120 extreme heatsink, asrock z68 extreme 4, 8gb corsair vegeance 1866mhz (4gb x 2), msi gtx 580 lightning, cooler master gx 750watt( rubbish), samsung spin point 1tb, running windows 7 ultimate 64bit

the result 

http://imageshack.us/photo/my-images/16/capture3bn.png/

http://imageshack.us/photo/my-images/808/capturedqu.png/

http://imageshack.us/photo/my-images/580/capture2jl.png/
thanks for any comment and advice, hope can teach me something, thanks alot, really     

between 5xxx something, gx 750 so noisy and sometimes its buzzing