You can also generally set the power limits on the CPU in the BIOS so going for a higher powered CPU and limiting it is an option. Then you can fine tune your performance/power balance. For example, I had a pair of E5-2643's which I limited to 95W with 115W boost (as opposed to 130W/156W). In practice it didn't make much difference, even to benchmarks. I think, as processes improved, later date processors had a real TDP some way below their markings.