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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..
Details
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.
NH-U9DO A3
Cooler Specification
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
Material
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
Warranty
6 Years
FAN Specification
Model
Bearing
Rotational Speed (+/- 10%)
1600 RPM
Rotational Speed with L.N.A. (+/- 10%)
1300 RPM
Rotational Speed with U.L.N.A. (+/- 10%)
1000 RPM
Acoustical Noise
17,6 dB(A)
Voltage Range
12 V
MTTF
> 150.000 h
NH-U9DO A3
22.06.2013 // ZeDen.net
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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)

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.

My unlocked Intel CPU is running too hot although my heatsink supports the specified TDP, what's the problem?

Intel's unlocked CPUs (K, X and C suffix) can dissipate more heat than indicated by the TDP specification if
  1. the TDP limits are extended or disabled in the motherboards' BIOS.
  2. the motherboard applies automatic overclocking by default, e.g. by raising the supply voltage of the CPU and using higher Turbo-Mode multipliers.
  3. some software creates untypical loads, e.g. Prime95 with AVX2 support and a) and/or b) apply.

This can lead to temperature issues, especially when using smaller coolers or compact cases.

The actual power draw of the processor can be monitored with software provided by the motherboard vendor or with 3rd party tools like HWInfo or HWMonitor.

If you encounter temperature issues (>90°C) and notice a higher than specified power draw, please ensure that no automatic overclocking is applied and limit the TDP to the specified value by choosing appropriate BIOS settings.

For Kaby Lake CPUs, it may also help to lower the CPU clock speed for applications that heavily use the AVX instruction set, which can lead to higher loads and power draw. This option is usually referred to as “AVX offset” and makes it possible to lower the multiplier specifically for AVX based applications without reducing performance when using other instruction sets. Depending on the quality of the CPU and the programs being used, a reduction of 2-3 steps usually gives very good results.

Please contact your motherboard vendor for details if you have trouble finding the appropriate settings in the BIOS.

All our TDP recommendations are based on thorough testing with the default values specified by Intel using popular applications such as Asus Realbench and prime95. Please note, however, that prime95 creates a particularly high load that goes beyond typical application scenarios and this leads to elevated temperatures. We thus recommend using other programs such as Realbench for checking the stability and temperatures of the CPU in realistic scenarios.

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