Might depend on what me mean by bottleneck. I submit for proof,
http://www.bit-tech.net/hardware/2013/06/12/intel-core-i5-4670k-haswell-cpu-review/5
Look at the shogun results. Of the "2500K" CPUs, only the 4670K at stock can cross 30FPS. The 3570K crosses on avg, while the 2500k at stock falls shot of 30FPS any way you look at it. I'm sure there are other cases where this will be true. The 2500K at stock will be "behind" other CPUs that are faster. It's still a good performer, but there might be cases out there where you'll want to OC it to get the performance from other chips.