Like other people, I've got an i7-4790k that ran at disturbingly high temperatures. The HSF is a Coolermaster Hyper 212+. It's not the latest and greatest solution, but certainly better than stock. My BIOS configuration was not set to overclock (I thought).
I'm running Linux Mint 17.1. When I would run prime95 with small FFT, the temperature *immediately* shot up to the high 90s and stayed there. Thanks to posts in this thread, I was clued in that XMP might be the cause. Sure enough, I had it enabled. Disabling XMP resulted in small FFT temperatures in the low 70s instead of the high 90s.
The only reason I enabled XMP was because I have PC2133 DDR3 memory that the BIOS wants to run at PC1600 by default. I thought the purpose of XMP was to use the correct memory timings specific to the DRAM modules? Why the heck is it also affecting CPU power consumption??