The 8700k tends to run rather hot, even at the default clockspeeds (which is 4.3GHz on all cores with TurboBoost on). The Hyper 212 isn't going to be enough to cool the chip because with TurboBoost enabled, TDP is thrown out the window entirely and the 8700k will generate well in excess of 120 Watts of heat vs. the stated 95 Watt TDP. The 212 would only be good if your turned TurboBoost off and ran at the 3.7GHz base clock. As said above, I would recommend a high end air cooler like the ones previously mentioned.