That 8GHz can only be possible when u run that 8 core chip on only 1 or maximum 2 cores running, u need to disable all other cores..... And for that u r gonna need a LN2 cpu cooler not water cooler. If u want to oc that chip then u must get an 990fx chipset motherboard. 970 chipset mobo will not give u much oc capacity but is a good option if u r not gonna oc and gonna use a single gpu. The Asrock Fatal1ty performance is the best 970 chipset mobo.
But if u r gonna oc the cpu or gonna use dual gpu config or gonna do both then only choice is 990fx motherboard (Dnt even think bout 970 mobo if u plan to oc). The Asus Sabertooth 990fx r2.0 and asus crosshair formula v are good choices. If u wanna oc as much as u can then get a sabertooth...