Noctua is known for quiet and effective cooling solutions typically topped off by uniquely-hued fans. The company's offerings carry premium price tags, but so do the Xeon Scalable and Xeon Phi processors that Noctua's LGA 3647 coolers are designed for. The DX-3647 family of coolers is designed for use exclusively with Intel's jumbo socket and has members with pairs of 92-mm or 120-mm fans, or a single 140-mm rotating air mover. All three new models have copper bases and heat pipes along with aluminum fin stacks.
The NH-D9 DX-3647 is the smallest of the bunch and uses a pair of fin arrays interleaved with two of 92-mm Noctua's NF-A9 PWM fans. Those spinners have a maximum rotational speed of 2500 RPM. The D9 is the the company's only offering for server builders using 4U enclosures. The key number among the D9's specifications is probably its 5.3" (13.4 cm) height.
Noctua's NH-U12S DX-3647 uses a pair of NF-A12x25 120-mm fans as the bread around a single aluminum fin array. The U12S is the heaviest of the bunch at just under 36 oz (1018 g) with its fans attached. The unit's 6.2" (15.8 cm) height means it isn't going to fit in a 4U server rack without a hot rod-style hole cut in the lid.
The NH-U14S DX-3647 is the biggest of the bunch at 6.5" (16.5 cm). Its 34-oz weight with its fan (957 g) is a little lower than that of the U12S, though. The cooler has mounting spots for both 120-mm and 140-mm fans for buyers who don't want to use the included NF-A15 spinner.
The Noctua NH-D9 DX-3647 and NH-U14S DX-3647 coolers come in at a cool $90 each at Amazon. Getting the middle child NH-U12S DX-3647 will require trading away a whole portrait of Benjamin Franklin. The company says all three LGA 3647 models will fit both the square and the narrow versions of Intel's plus-sized server socket. The manufacturer backs the coolers with a six-year warranty.