Data from Hardware.fr review:
Lol, a 4C/4T Core i5 6600K manages to almost match octo-core 4GHz+ FX8350 in MT applications at stock. With OC it will be able to beat the FX9590 power hog in many highly-threaded apps and absolutely demolish it in anything that doesn't scale past 4 threads.
Now when it comes to games Core i5 6600K was almost 40% faster than FX8350 and 28% faster than FX9590 overall. Even in those modern games that fanboys use to showcase FX like Crysis 3 and Watch Dogs the Skylake Core i5 was faster than FX9590. I kinda get why some people are putting their hopes on DX12 miracles now.
CP5670 said:
I guess I can ignore this launch and keep my 4790K for the foreseeable future. The 6700K is only 5-6% faster according to AT, even less in games, and it doesn't overclock any better or even have the big L4 cache of the 5775C. It might make more sense for Sandy Bridge owners.
It's actually more in games than applications. Take a look at Hardware.fr, Hardware Canucks, HardOCP, Eurogamer and other reviews (preferably those tested using DDR4-2666 or faster RAM).