Well - the performance difference between 1600mhz and anything above is not something I'd worry about; since I got ram, which is faster than 1300mhz (what could, as far as I know, limit the overall system's performance).
Phew...what drops and titles...spontaneously:
I noticed huge drops in Borderlands2 for example (lowering the settings didn't help that much -> yes, could be cpu related) - these drops go down to like 35 in fights and (with vsync) to 45-50 while looking over a bigger area.
Also AC4 kinda' sucks...but that could be uibsoft's fault, since it is poorly optimized.
I also noticed drops in Warframe (with and without vsync) in bigger fights, where the fps drop from 200-120 to 45.
That's all I could tell you atm