Noctua NH-D9 DX-3647 4U server cooler review for Xeon Phi/Scalable

Initially, the Intel LGA-3647 platform was created for cloud computing, which requires a high density of CPU cores in one CPU socket, but over time there were good motherboards for workstations on Xeon Scalable, and this year this CPU socket and does loomed as a top solution for enthusiasts who are ready to buy 28-core Xeon W-3175X and motherboards such as Gigabyte C621 Aorus Xtreme or Asus ROG Dominus. But, of course, solutions from Asus and Gigabyte - is rather a piece product for some special cases, and the mass use of processors Xeon Phi and Xeon Scalable - it’s still servers and workstations.


Coolers for LGA-3647 are on sale very rarely, and mainly when assembling a server or a working machine, you will be offered OEM cooling from Dynatron or Supermicro companies, that is, those solutions where no one thought about the noise level. Noctua has two models for this socket: NH-U14S, NH-U12S, and NH-D9 4U with DX-3647 indexes. Because of the gigantic size of the socket, these coolers are not compatible with any other CPU connectors, and each of these models is designed for specific needs. For example, the NH-U14S 140mm with fan for desktop workstations, which is important for quiet operation, the NH-U12S a version of it with the new Noctua fans A12x25PWM, and NH-D9 4U is a compact cooler with a height of 134 mm, which will not interfere with any neighboring memory modules or PCI Express cards.

All three Noctua coolers have two types of mounts: Narrow Type and Square Type, so they are compatible with all motherboards under Socket 3647.


Structurally, NHD 9DX-3647 4U is a twin turret for a pair of 92 mm fans installed under the scheme “pull-push”. One fan is planted in the radiator section, between the ribs, and the second - outside. When installing both fans will have to be removed, so you can experiment and reinstall them in any other way, the benefit of universal mounting allows it.

The NF-A9 HS-PWM fans have PWM speed adjustment, and a power splitter is supplied so you can connect the cooler to one cpu_fan1 connector of the motherboard. However, if your motherboard has power connectors OPT_FAN, where you can adjust the dependence of the fan speed on the CPU temperature, it is better to connect the cooler to the two power sockets to keep the ability to monitor its performance.

Each fan has rubber corners on both sides to reduce vibration and small grooves in the working area of the body on the side of the blades designed to reduce spurious noise. The minimum speed of each fan - 400 RPM, so that even without the tricks in the design can achieve silent operation.


Rotor suspension - the most modern hydrodynamic with magnetic alignment (SO2) - reliable design without friction, providing complete absence of vibration and as a result, time between failures more than 150 000 hours (17 years). The company Noctua gives its coolers 6 years warranty, which is a record in the market of cooling systems. At a maximum speed of 2500 RPM, the fan has a noise level of 30.6 dB at a performance of 56 CFM.

The radiator Noctua NH-U9DX-3647 4U has 4 U-shaped heat-conducting tubes with Nickel-plated protective coating. When installing the radiator plates, soldering is used, as a result of which the radiator turns out to be eternal, and there is no fear of detachment of the plates from vibration.


The radiator Noctua NH-U9DX-3647 4U has 4 U-shaped heat-conducting tubes with Nickel-plated protective coating. When installing the radiator plates, soldering is used, as a result of which the radiator turns out to be eternal, and there is no fear of detachment of the plates from vibration.

Previously, Noctua supplied complete with coolers syringe with thermal paste, but now saves and applies a layer of thermal interface directly to the sole of the cooler. Of course, processors in servers and workstations are rarely changed, and such a step will seem logical to someone, but not to us. I believe that the thermal interface should be supplied in a syringe.

The treatment of the base is very interesting: we have here not mirror polishing, but with small notches that you can feel even with your nail. Theoretically, if you have a thermal paste with high fluidity, this treatment increases the area of thermal contact with the heat distributor of the processor. From a practical point of view, to measure the difference in temperature between the mirror polishing and honing this expedient means can not be measured. But here it is necessary to understand that not only marketers, but also real engineers work at the headquarters of Noctua, and if you read their interviews, they are very proud when such simple methods can reduce the temperature by 0.1-0.2 degrees Celsius. What can I say - romance!


Due to the fact that the cooler is very compact, it does not cover the memory slots if it is sideways to them. But even in this case, the nearest memory module has to be installed at an angle, and if the memory is higher - it would touch the radiator.

On dual-processor motherboards, two Noctua NH-U9DX-3647 4U coolers can be installed one after the other, obtaining a cooling system with 4 fans installed in series. Do not be afraid that the warm air from the first processor will lead to overheating of the second: the high temperature of the air at the input is compensated by a higher flow rate in the second cooler, so that in practice the temperature will be approximately the same.

As already noted by the manufacturer, there are no problems with PCI Express cards, even on EEB motherboards that have 7 expansion slots.


  • Intel-Intel Xeon Gold 5120 (14C / 28T, 3.2 GHz, TDP 105W)
  • Motherboard - ASRock motherboard for clothes EP2C621D12-WS
  • 32 GB DDR4 ECC REG
  • VMware VSphere ESXi 6.7
  • Windows 10 for 64-bit (6 cores, module, hardware virtualization support, module)
  • Prime95 Test


That Noctua cooler can handle 105 Watt CPU, I do not doubt. In automatic mode for the model in question, it makes sense to adjust the speed adjustment one step lower to the fans accelerated earlier.


Noise level 1 cooler Noctua NH-U9DX-3647 4U at maximum speed is 39.6 dB. When installed as a pair on our motherboard, the noise from the four fans rises to 42.3 dB.

Chart of noise level has a very pronounced surge in the area of 280 Hz. The main source of noise is the fan motors, so in most cases, when the computer is not running at maximum performance, this noise will not. At speeds in the region of 500 RPM, the coolers work silently, and you can use your computer to edit multimedia content without fear that it will take out the whole brain with its buzz.


Noctua NH-D9 DX-3647 4U is a universal cooler for Xeon Scalable processors, which can be simply kept in stock if you are a collector, and you periodically order servers on this Intel platform. It is equally well suited for rack buildings, and for “turrets”, which are equipped with a workplace specialist. On processors of the Xeon Bronze / Xenon Silver series it is possible to tell that in a typical operating mode everything will be very silent, but under loading the low-frequency rumble will quickly get bored.

As an alternative to liquid cooling, Noctua primarily offers its quality: solder in the radiator and two fans, which can be easily replaced by others if desired. But it should be understood that for older processors Xeon Scalable with a capacity of 200 W is better to choose a liquid cooling system.