4) CPU bottleneck?
In a CPU bottleneck situation you are most afraid of the minimal frame rate drop (i will explain and proove that statement in my other CPU dedicated benchmark) and don't care that much about maximum frame rate.
How much FPS would drop if i lowered the Core i7 3820 to 4 GHz?
Without bothering you with new charts, i will just state the difference in minimal frame rate going from 4000 MHz to 4550 MHz in %.
Alan Wake - 0 %
Aliens vs. Predator - 0 %
Avatar - 2 %
Cryostasis - 0 %
Crysis 2 - 0 %
Deus Ex Human Revolution - 0 %
Formula 1 - 3,5 %
F.E.A.R. - 0 %
Hard Reset - 7 %
H.A.W.X - 21 %
Homefront - 0 %
Lost Planet - 2 %
Necrovision - 0 %
Red Faction Armageddon - 1,5 %
Serious Sam 3 - 1,5 %
S.T.A.L.K.E.R.: Clear Sky - 0 %
Syndicate - 0 %
World In Conflict - 8,5 %
CONCLUSION: there is almost no bottneck for GTX670 when CPU speed is 550 MHz lower. Only Hard Reset, World In Conflict and H.A.W.X would benefit from CPU OC.