Noctua’s DX line CPU coolers have become a default choice in premium grade quiet cooling solutions for Intel Xeon processors. The NH-U12S DX-3647 features a larger, custom-designed contact surface and supports both square and narrow type LGA3647 platforms. Based on the proven, 120mm size NH-U12S heatsink and equipped with two of Noctua’s award-winning, PWM controlled NF-A12x25 120mm fans, it provides an excellent balance of performance, compatibility and quietness of operation. Topped off with the professional SecuFirm2™ mounting system and pre-applied NT-H1 thermal compound, the NH-U12S DX-3647 forms a complete premium quality package for quietly cooling LGA3647 based Xeon workstations and servers.

Please note that the NH-U12S DX-3647 is a dedicated version for the Intel LGA3647. Due to its customised larger base, it cannot be used on any other sockets and is incompatible with Noctua’s standard mounting kits.
DX series for Intel Xeon

DX series for Intel Xeon

First introduced in 2008, Noctua’s DX line CPU coolers have become a standard choice when it comes to quiet, premium grade air cooling solutions for Intel Xeon processors. Thanks to their superior acoustic efficiency, they are ideal for workstations and servers that run in noise sensitive environments (e.g. audio/video production, content creation, engineering, etc.).
Customised for LGA3647

Customised for LGA3647

The new DX-3647 line coolers are dedicated, customised solutions for Intel’s professional LGA3647 platform, which makes them an ideal fit for both Skylake-SP based Xeon Scalable CPUs (Platinum, Gold, Silver or Bronze, Purley series) and Xeon-Phi processors (code names Knight’s Landing or Knight’s Mill).
Enlarged contact surface

Enlarged contact surface

At 70x56mm, the heatsink’s copper contact surface is more than double the size of the standard model. Tailored to fit the enormous integrated heat-spreaders (IHS) of Intel’s LGA3647-based processors, this customised design allows for an optimal heat flow from the CPU over the base to the heatpipes and on to the cooling fins.
Supports square and narrow type LGA3647 sockets

Supports square and narrow type LGA3647 sockets

The heatsink’s SecuFirm2™ mounting system includes two sets of brackets in order to support both square and narrow type LGA3647 sockets. Thanks to pre-installed mounting screws and the included processor clips (square type and narrow type without Omni-Path fabric connector, with fabric connector on request), the installation procedure is easy, quick and secure.
120mm size for excellent performance and compatibility

120mm size for excellent performance and compatibility

With five heatpipes and two next-generation NF-A12x25 120mm fans, the NH-U12S DX-3647 achieves outstanding cooling performance while maintaining excellent compatibility: At 158mm height and 125mm width, it is short enough to fit most modern tower cases and stays clear of the top PCIe slot on many motherboards.
Dual NF-A12x25 PWM fans

Dual NF-A12x25 PWM fans

The NH-U12S DX-3647 is equipped with two of Noctua’s award-winning, next-generation NF-A12x25 120mmm fans. This exquisite, state-of-the art push/pull dual fan configuration allows it to achieve a remarkable level of quiet cooling performance despite its relatively compact size.
PWM support and y-cable

PWM support and y-cable

The NF-A12x25 premium fans supplied with the NH-U12S DX-3647 support PWM for convenient automatic speed control through the motherboard, which allows them to run near silent at lighter loads and to speed up only when necessary. The supplied y-cable makes it possible to power and control both fans simultaneously from a single motherboard fan header.
Pre-applied NT-H1 thermal compound

Pre-applied NT-H1 thermal compound

Noctua’s much-acclaimed NT-H1 is a pro-grade TIM solution that provides minimum thermal resistance and outstanding long-term stability. Having the paste pre-applied to the heatsink base ensures optimal bond-line thickness and saves precious time in installation. Ideal for system integrators!
6-year manufacturer’s warranty

6-year manufacturer’s warranty

Noctua products are renowned for their impeccable quality and outstanding longevity. True to this legacy, the NH-U12S DX-3647 heatsink is built to last, and like all Noctua fans, the supplied NF-A12x25 units feature an MTTF rating of more than 150,000 hours. The entire package comes with a full 6-year manufacturer’s warranty.
NH-U12S DX-3647
Notes and warnings
Please note that the NH-U12S DX-3647 is a dedicated version for the Intel LGA3647. Due to its customised larger base, it cannot be used on any other sockets and is incompatible with Noctua’s standard mounting kits.
Cooler Specification
Intel Xeon LGA3647
Height (without fan)
158 mm
Width (without fan)
125 mm
Depth (without fan)
45 mm
Weight (without fan)
626 g
Height (with fan)
158 mm
Width (with fan)
125 mm
Depth (with fan)
97 mm
Weight (with fan)
1018 g
Copper (base and heat-pipes), aluminium (cooling fins), soldered joints & nickel plating
Max. TDP
see TDP guide
Fan compatibility
Scope of delivery
  • 2x NF-A12x25 PWM fan
  • 4-pin Y-cable
  • NT-H1 high-grade thermal compound (pre-applied)
  • SecuFirm2™ mounting-kit for LGA3647
  • Noctua metal case-badge
6 Years
FAN Specification
Max. rotational speed (+/- 10%)
2000 RPM
Min. rotational speed (PWM, +/-20%)
450 RPM
Max. acoustical noise
22,6 dB(A)
Input power
1,68 W
Voltage range
12 V
> 150.000 h
NH-U12S DX-3647
17.12.2018 // eTeknix.com

NH-U12S DX-3647 Review

In terms of its performance, the testing figures speak for themselves. Beyond the cooler design itself, which can only do so much, the fans were clearly more than capable of not only keeping our system cool, but also doing so at impressive low noise levels. [...] Whether you’re building a one or two-socket server with LGA3647 chips, the NH-U12S DX-3647 will do an awesome job. It will keep your chips well within optimal operating temperature, even when they’re taxed to the maximum.
Test verdict: "This is a superb CPU cooler." (Bohs Hansen, eTeknix.com)
16.06.2019 // blog.livedoor.jp

NH-U12S DX-3647 Review

先日レビューした「Noctua NH-U14S DX-3647」は150mmラウンドフレーム型ファン搭載かつ大型ヒートシンクによる高い冷却性能の反面、横幅が大きいためPCIEスロットと干渉しやすいという欠点がありましたが、「Noctua NH-U12S DX-3647」は標準的な120mmサイズ冷却ファン搭載モデルなので、PCIEスロットと干渉が発生し難く、また全高42mmまでのヒートシンク付きメモリならファンのオフセットなしで使用できる互換性の高さが魅力です。 「Noctua NH-U14S DX-3647」に比べると冷却性能では多少劣りますが、それでも300Wクラスの発熱を十分に御しきれるCPUクーラーなので、PCIEスロットやメモリと干渉が発生し難いところと相まって、扱いやすさが光るスタンダードモデルです。 シルバーアルマイトで表面処理された大型のアルミ放熱フィンを搭載するヒートシンクは工業製品的な美しさがあるものの、Noctuaを代表するベージュ&ブラウンのカラーリングの冷却ファンはかなりユニークなのでNoctua NH-U12S DX-3647は総じて人を選ぶデザインだと思います。
Test verdict: "冷却性能の検証結果からもわかるように「Noctua NH-U12S DX-3647」は、最大で300W超クラスの電力負荷になる28コア56スレッド「Intel Xeon W-3175X」をサーマルスロットリングさせることなく安定して運用することができる冷却性能を発揮しました。「Intel Xeon W-3175X」はTDP255WとなっておりLGA3647プラットフォームで提供されるIntel Xeonスケーラブルプロセッサー最上位モデルのXeon Platinum 8280でさえもTDP205Wなので、「Noctua NH-U12S DX-3647」は基本的に全てのIntel Xeonスケーラブルプロセッサーに対応できます。"
15.08.2018 // GreenTechReviews.ru

NH-U12S DX-3647 Review

Noctua NH-U12S DX-3647 – высокоэффективный и очень тихий процессорный кулер, который способен остудить пыл любого существующего на данный момент процессора в исполнении LGA3647. Проработанная конструкция радиатора с набором из пяти тепловых трубок, огромное идеально ровное основание и пара новейших вентиляторов с очень низким уровнем шума даже на максимальных оборотах – всё это достоинства NH-U12S DX-3647. К недостаткам отнести ничего не вышло – совместимость с материнскими платами (в плане PCIe слотов) тут больше зависит от самих плат, а изменение конструкции радиатор в форм-факторе 120 мм попросту невозможно – сдвинуть радиатор в область подсистемы питания процессора не представляется возможным – там находятся не только высокие радиаторы, но и производится подключение нескольких кабелей питания. Поэтому надо уделить внимание этому должное внимание при подборе компонентов для сборки системы. Что касается цены, то она очень мала в сравнении с ценниками на все оставшиеся комплектующие. Мало того, мы считаем, что она полностью справедлива для продукта столь высокого качества.
Test verdict: ""Noctua NH-U12S DX-3647 – высокоэффективный кулер формата 120 мм, который является бескомпромиссным решением для систем среднего размера!" (Солонин Владимир, GreenTechReviews.ru)
24.07.2018 // XtremeSystems.org

NH-U12S DX-3647 Review

Noctua does it again. For people wanting to keep it simple, air cooling is about as simple as it gets. All three coolers from Noctua are very capable and allow flexibility for different case constraints. The combination of Noctua’s easy installation process plus top end performance makes the DX-3647 line of collers for LGA3647 platform an amazing choice for the first time builder or established enthusiast. You would be hard pressed to find a better tower cooler option in this range with this combination of performance, style, and operating noise levels. When you get to the point of making a choice on your cooling solution for your new LGA3647 platform, you really cannot go wrong with the DX-3647 Coolers. They have got enough technology built in to make your head spin, runs dead silent, looks great, fixes one of the greatest cooling challenges, and comes with a six-year warranty to make sure you are happy with your purchase in the long term. The suggested retail prices are as follows:
Test verdict: "Noctua does it again... You would be hard pressed to find a better tower cooler option in this range with this combination of performance, style, and operating noise levels." (Ambrosidou Nat, XtremeSystems.org)
04.07.2018 // Phoronix.com

NH-U12S DX-3647 Review

The SNK-P0068APS4 led to an average temperature of 31C at its full fan-speed while the Noctua NH-D9 DX-3647 4U had an average temperature of 23.5C with its fans at their full speed or 38.8C when using the automatic fan control enabled via the BIOS. The minimum and maximum core temperatures were also aligned with expectations. The Noctua heatsink did a nice job of allowing this Intel Xeon Silver CPU to run extremely cool inside this 4U chassis even at full load.
Test verdict: "From compiling the Linux kernel to running Python scripts to the many other workloads tested, the Noctua Xeon Scalable 4U heatsink was doing a great job at keeping the system running cool, especially at full-speed but even with the automatic fan control it was doing a great job. Even at full-speed, the NF-A9 fans were barely audible outside of the steel Rosewill 4U chassis, especially if you are running multiple systems in the room." (Michael Larabel, Phoronix.com)

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Installation Manual (PDF)

Information Sheet (PDF)

How should I clean my Noctua cooler?

Dust: Fans and heatsinks inside computer cases tend to accumulate dust over longer periods of usage. In order to maintain maximum performance, please clean your fan and heatsink regularly. For cleaning, please first remove the fan from the heatsink and clean it using a duster, slightly moist tissue or canned air. Please be careful not to use too much force in order to prevent any damage to the fan. Please do not use a vacuum cleaner as this may apply excessive force to the fan and do not put the fan under running water as water residues inside the motor may lead to short circuits. Please also note that the fan is not designed to be taken apart by the user. Removing the impeller from the frame will break the sealing of the bearing and results in a loss of warranty. Before reinstalling the fan, clean the heatsink itself with a duster or vacuum cleaner. Do not use water to clean the cooler. Finally put the fan back on and connect it to your motherboard fan header or fan controller.
Thermal paste residues: Whenever you take off the heatsink from the CPU, we recommend to clean the CPU as well as the base of the cooler before re-applying thermal paste and re-installing the cooler. You can either just wipe the base and the CPU clean with a dry, lint-free tissue or, for more thorough cleaning, use a lint-free tissue moistened with either a mild solution of washing-up liquid or isopropyl alcohol. Do not put the cooler or CPU under running water. Note that both the base of the heatsink and the CPU should be dry, free from residues of thermal compound and free from grease before re-applying thermal paste and re-installing the cooler.

What Thermal Design Power (TDP) is this cooler recommended for and how much Watt (W) of heat can it dissipate?

Please refer to our CPU compatibility list for information on maximum recommended TDP and heat dissipation.

Can I install a Noctua cooler in my system from Acer, Dell, HP or Lenovo?

Systems from Acer, Apple, Dell, HP, Lenovo or other major brands often use motherboards which differ slightly from the specifications issued by Intel and AMD. While those changes are usually subtle, they can lead to compatibility issues with coolers that were built to comply with these specifications.

Even in case the cooler is mechanically compatible and can be installed, other issues can occur, e.g. proprietary fan connectors, BIOS errors due to a low fan speed, shutdowns, etc. Some of these problems can be avoided with some technical knowledge, but especially BIOS related issues can often not be resolved.

Due to the large number of possible issues that cannot be resolved with different mounting parts alone, Noctua does not officially support systems from Acer, Apple, Dell, HP, Lenovo or other major brands.

My case supports CPU coolers of up to XXXmm height, which model should I choose?

Please refer to our TDP guide in order to select the cooler that offers the best cooling performance at a given height.

I have difficulties installing the cooler, can you help?

Please refer to the installation manual and our video installation guides for detailed instructions on how to install the cooler.

Which Noctua fan or CPU cooler should I buy? How to choose the right model?

Not sure which Noctua product to buy? Our detailed buying guides for fans and CPU coolers help you to choose the model that works best for you.

How can I determine if the motherboard’s UEFI BIOS is overclocking my processor by default and deactivate this automatic overclocking?

Most motherboard vendors allow their overclocking-enabled products (e.g. those with Intels X- or Z-series chipsets) to run the processor at increased clock speeds by default, without requiring any user action at all. Since TDP (Thermal Design Power) limits are usually also disabled by default, this leads to the CPU exceeding the rated TDP to a varying degree, depending on the used applications and their workloads. Due to the increased heat output of the CPU, you may see higher CPU temperatures than expected.

In order to find out if your motherboard is overclocking your processor by default, please enter the UEFI BIOS and select the “advanced” or “overclocking” menu. There you should be able to find options such as “MultiCore Enhancement” (options: enabled/disabled), “CPU Ratio Apply Mode” (options: all/per core) or similar. To disable the automatic overclocking, adjust the settings either to “disabled” or “per core” and make sure that the individual multipliers match the original specifications.

In doubt, please contact your motherboard vendor for detailed instructions on how to disable this feature.

Is it possible to use the cooler with vertical graphic cards?

Depending on the chassis, card and motherboard being used, installing PCIe cards in a vertical position using riser cards may cause compatibility issues with CPU coolers. Whether there will be a problem or not depends on the exact position of the card (which is determined by the PC case and/or optional vertical GPU holder bracket), the width of the card as well as the position of the CPU socket on the motherboard. In order to verify that there is sufficient space for the cooler, please measure the distance between the centre of the CPU socket and the top of the PCI card in order to make sure that the cooler fits.

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