I am going to buy a new PC with 680 gtx Sli. If I equip it with a i7 3820 not overclocked (i.e. standard 3,6 Ghz), could the 680 gtx Sli be limited by the CPU? Would a i7 3930k be a better choice? Worth spending more money? I am going to play at 1920x1080 with all filters on AA AF AO Vsync. Thanks.