the ram isn't even that tall, 42mm neo forza ddr4. check out noctua and be quiet!'s documents on ram clearance before making a decision to save a headache. Thermalright Peerless Assassin 120 SE or Deepcool AK620 would be better picks. Nearly as good as the D15 but much cheaper.
These are my temps on cinebench. "Best turbo/overclocking headroom", so yes. "Standing 158mm tall, the NH-U12A is short enough to fit most modern mid- or high-end tower cases." U12A absolutely fine for me on a 12700K. Admittedly, I am using a high airflow case (Corsair 7000D) but am also only running 2x intake and 1x exhaust. The Noctua NH-D15 is the next-best performer, at 37 degrees, 41 degrees, and 36.6 degrees for our three VRM measurement points. The Zalman CNPS20X has roughly the same VRM2 measurement reading at D1hTu.