Ok putting together a i5 3570k build for my son with a gigabyte z77 d3h. To save money I have two 6gb triple channel kits of 1600 ddr3 spare, a corsair kit timmings 8, 8, 8, 24 & a Kingston kit timmings 9, 9, 9, 27. Would it be better to just use 4gb in dual channel or would 6gb be quicker in single or mix both kits for 8gb at the slower timmings assuming they play nicely together ?