Thanks, Sean!
Your small manual on oc'ing is very useful for all, i think.
I will give it a try 8)

Answer: vCore wasn't changed. It is at 1.3250V.

Yes, memory is in the black slots and i think, i'll gonna buy 1600Mhz memory.
Memory and a stock cooler are the weakest points in my system for now.
First of all - temperature. CPU must be cold in the summer time.