Intel Core i3 2120
C-Ray is an extremely well tuned multi-threaded ray-tracing benchmark. The Core i5 2500K with its four physical cores was more than twice as fast as the Core i3 2120.
Smallpt also heavily favors the Core i5 2500K, but there is a small improvement out of the extra 200MHz on the Core i3 2120.
An extra 200MHz out of a Core i3 SNB yields around a 6% improvement for the x264 multimedia benchmark.