NH-U12S model running at 11700kf
NH-U12S model running at 11700kf
I won’t be increasing its speed, and it’s set at 5000x from Corsair.
From the feedback I've seen, the 5000X offers solid airflow in its standard setup. Initially, I doubted it would perform well since sealed front panels usually limit airflow, but reports from TechRadar and PCInvasion suggest otherwise. You should be fine if those sources are trustworthy. To verify, Noctua's Compatibility Centre confirms that the NH-U12S pairs nicely with the 11700KF (https://ncc.noctua.at/cpus/model/Intel-C...700KF-1285).
Multicore Enhancement is an overclock adjustment. It modifies the CPU's boosting process so every core operates at peak speed. Here, it raises performance to 5.0GHz across all cores instead of the standard 4.5GHz. This is definitely an overclock and will increase power consumption. If you mean eliminating power restrictions (like removing the Tau boost duration cap), that isn't an overclock and should be acceptable. It will generate more heat, but a U12S model is capable of handling it.
It should work fine with the U12S, though the NH-D15 would really prevent thermal issues. Those final 500MHz parts are expensive in power use, so upgrading to something stronger makes sense. The biggest drawback of the D15 is possible RAM clearance problems, but if that’s not a concern, it offers top performance cooling.