760 and you will probably hit a bottleneck in some things and not in others. the specific bottlenecks i couldnt say. probably more bottlenecks than you would like. an overclock would help a bit.
see it isnt as simple as needing an (x) powerful cpu to drive a
powerful gpu. some games will have a higher cpu:gpu ratio than others. it all comes down to the individual game and settings.
the lower the graphical settings the more fps you will get but the higher the cpu requirements. there comes a point with a marginal cpu where you cant turn the graphical settings down anymore for more fps because the cpu has reached capacity. that, is a bottleneck. it's not always there but can present itself in the right scenario.