It will all depend on your individual CPU, some will OC great, others not worth a darn. Might start with the vCore (CPU voltage at about 1.25 and start raising the multiplier while keeping an eye on temps (Core temp is a good free app)
You might run out of voltage before you temperatures get too high. Set the voltage to get the temperatures you are happy with and then increase the multiplier and see where that gets you, You should get to 4.6Ghz, if the chip will do it.
It will all depend on your individual CPU, some will OC great, others not worth a darn. Might start with the vCore (CPU voltage at about 1.25 and start raising the multiplier while keeping an eye on temps (Core temp is a good free app)
Contrary to popular belief, a 212 Evo can handle an X99 overclocked CPU, in my case it was a 5820K at 4Ghz. I bought a Noctua for a 4.5Ghz OC though. A 212 Evo will be fine for any overclock your 6600K will reach.