4ghz is no problem trigger, this board and that cpu walk in the park. That aint my buddy with the ram, i have just seen that he is selling all kinds of his stuff lately, and i noticed that the dominators he is selling did 2150mgz on his 790i board, and there tripple channel, but the bad thing about it, cas 9, im not interested in anything cas 9, cas 8 i would have bought them, i dont know much about the spd thing your talking about.

You going to have to play with the gtl voltages for sure, quads overclock very differently than dual cores.