Noctua's DO line of coolers has become a default choice when it comes to quietly cooling AMD Opteron CPUs. Upgrading both compatibility and performance, the new A3 model features Noctua's professional NM-A3 SecuFirm2™ mounting system that not only supports socket G34, C32 and F, but also allows to install the cooler turned by 90°. Thanks to six heatpipes, a performance optimised fin stack and its two premium grade NF-B9 92mm fans, the compact NH-U9DO A3 cools Opteron processors up to a thermal design power (TDP) of 115W at minimum noise levels. Bundled with Noctua's industrial-grade NT-H1 thermal compound and fitting standard 4U chassis, the NH-U9DO A3 forms a complete premium quality package for quietly cooling AMD workstations and servers.

  Caution:  Due to its more compact design and quiet operation, the NH-U9DO A3 is approved only for processors with up to 115W thermal design power (TDP). Using the NH-U9DO A3 on higher TDP processors may be possible with increased case ventilation depending on the specific configuration but is not officially supported by Noctua..
Performance optimised design

Performance optimised design

The NH-U9DO A3 is based on Noctua's much acclaimed NH-U series which have received more than 300 awards and recommendations from the international press. Six heatpipes, a performance optimised fin stack and an enlarged contact surface suitable for socket G34 allow for further improved performance.
Supports G34, C32 and Socket F

Supports G34, C32 and Socket F

Thanks to the new NM-A3 SecuFirm2™ mounting system that includes brackets with both 3.5" and 4.1" hole spacing, the NH-U9DO A3 supports Socket F as well as the newer G34 and C32 sockets.
Can be turned by 90° for optimal compatibility and positioning

Can be turned by 90° for optimal compatibility and positioning

Noctua's NM-A3 SecuFirm2™ mounting system makes it possible to install the cooler rotated by 90° in order to allow for an optimal positioning of the cooler and to evade compatibility issues on dual socket mainboards.
Drop-in replacement for standard AMD coolers

Drop-in replacement for standard AMD coolers

Screwing directly to the standard AMD backplate, the NM-A3 SecuFirm2™ mounting system makes the new A3 revision a true drop-in replacement. Choose the appropriate mounting brackets, fix the two spring screws and you're done!
2x NF-B9 92mm premium fan

2x NF-B9 92mm premium fan

Featuring advanced aerodynamic optimisations and Noctua's premium-grade SSO-bearing, the award-winning NF-B9 is renowned for its exceptional quietness and long-term stability. The dual fan configuration allows for increased performance and safeguarding against failure.
NT-H1 thermal compound

NT-H1 thermal compound

Noctua's much-acclaimed NT-H1 is a well proven pro-grade TIM solution that provides minimum thermal resistance, excellent ease-of-use and outstanding reliability, which makes it suitable for use in professional server and workstation environments.
Cooler Specifications
AMD G34, C32, F (3.5" & 4.1")
Height (without fan)
125 mm
Width (without fan)
95 mm
Depth (without fan)
71 mm
Height (with fan)
125 mm
Width (with fan)
95 mm
Depth (with fan)
95/120* mm
Weight (without fan)
540 g
Weight (with fan/s)
630/720* g
Copper (base and heat-pipes), aluminium (cooling fins), soldered joints & nickel plating
Fan compatibility
2x 92x92x25mm
Scope of Delivery
  • 2x NF-B9 premium fan
  • 2x Ultra-Low-Noise Adaptor (U.L.N.A.)
  • 2x Low-Noise Adaptor (L.N.A.)
  • Y-Split Cable
  • NT-H1 high-grade thermal compound
  • SecuFirm2™ Mounting Kits
6 Years
FAN Specification
Rotational Speed (+/- 10%)
1600 RPM
Rotational Speed with L.N.A. (+/- 10%)
1300 RPM
Rotational Speed with U.L.N.A. (+/- 10%)
1000 RPM
64,3 m³/h
Airflow with L.N.A.
52,6 m³/h
Airflow with U.L.N.A.
41,1 m³/h
Acoustical Noise
17,6 dB(A)
Acoustical Noise with L.N.A.
13,1 dB(A)
Acoustical Noise with U.L.N.A.
7,9** dB(A)
Input Power
1,32 W
Voltage Range
12 V
> 150.000 h
22.06.2013 // ZeDen.net

NH-U9DO A3 Review

Au final on a un produit très performant et assez silencieux. Du moment qu'on possède un boitier bien ventilé, ces radiateurs suffisent amplement à refroidir les 135 W produits par chacun de nos processeurs de test. C'est assez impressionnant de voir qu'un ventirad de seulement 92 mm arrive à faire ce que fait généralement un 120 mm.
Test verdict: "Un petit ventilateur pour de grosses performances, le NH-U9DO-A3 est au final un produit de grande qualité, made by Noctua." (Paul-Emmanuel Xueref, ZeDen.net)

Installation Manual (PDF)

Which Noctua coolers are compatible with LGA1150?

The mounting is identical on all LGA115x sockets (LGA1150, LGA1155, LGA1156). The following coolers are thus compatible with LGA1150 out of the box and don’t require any upgrades in order to be used on this platform: NH-C12P SE14, NH-C14, NH-D15, NH-D14, NH-L12, NH-L9i, NH-U14S, NH-U12S, NH-U12P SE2, NH-U9B SE2. In addition, all older models which have been upgraded with the NM-I3 kit can also be used on LGA1150 without any further upgrades.

The following coolers can be made compatible to LGA1150 using the NM-i115x Upgrade-Kit and are eligible for Noctua’s free mounting kit offer: NH-C12P, NH-U12, NH-U12F, NH-U12P, NH-U12P SE1366, NH-U9, NH-U9F, NH-U9B.

The following coolers can be made compatible to LGA1150 using the NM-i115x Upgrade-Kit but are not eligible for Noctua’s free mounting kit offer: DX-Series Xeon coolers, NH-D14 SE2011.

The following coolers are mechanically incompatible with the NM-i115x Upgrade-Kit and can not be made compatible with LGA1150: DO-Series AMD Opteron coolers, NH-L9a.

Which sockets are supported or can be supported using upgrade kits?

Please refer to our socket compatibility chart.

I'm experiencing fan speed issues with my motherboard from Supermicro, what can I do?

The BIOS of many motherboard models from Supermicro expects a certain minimum fan speed (usually 700rpm), which is higher than the minimum fan speed that can be achieved with Noctua's PWM fan models. The BIOS may interpret the low minimum RPM of Noctua fans as a fan error and thus try to run the fan at 100% for a short period before going back to automatic control.. This can result in oscillating fan speeds and fan speed warnings in the BIOS or the fan management console.

Unfortunately there is usually no option to set a lower minimum value that would suit the low minimum speed of Noctua PWM fans.The issue can thus only be resolved by either disabling automatic fan speed control in BIOS, which will cause the fans to run at a constant speed, or by requesting a modified BIOS file from Supermicro, which takes the minimum fan speed of Noctua fans into account (charges might apply).

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