We tackled this CPU cooler because we needed to find some cooling solutions for another review, the Dan A4 SFX mITX case.

With the rising demand for smaller cases it gets harder and harder for a low profile coolers to handle the enthusiast market needs.

At just a mere 37 mm in total height including the fan, will a cooler with such a small footprint be up to the task?
Let’s find out together.


First about Noctua :


Established in 2005, Noctua took international silent enthusiasts’ hearts by storm and quickly developed into one of the most acclaimed suppliers of premium quality quiet cooling products. Today, Noctua is present in more than 30 countries across the globe and working with several hundred sales partners. Chosen by noise-conscious PC users, system integrators and industry clients alike, Noctua has become synonymous with impeccable quality, excellent customer service and class-leading quiet cooling performance.

Designed in Austria, Noctua’s premium cooling components are internationally renowned for their superb quietness, exceptional performance and thoroughgoing quality. Having received more than 6000 awards and recommendations from leading hardware websites and magazines, Noctua’s fans and heatsinks are serving hundreds of thousands of satisfied customers around the globe.



Pricing and availability


*At the time of the review:

£ 34.99 – via Amazon.co.uk

Noctua NH-L9i – processor cooler

$ 39.95 – via Amazon.com

Noctua Low-Profile Quiet CPU Cooler for Intel 115x Based Retail Cooling NH-L9I


Presentation and specification


*Courtesy of their website:

  • Due to the slim 23mm heat sink and the NF-A9x14 low profile fan that measures only 14mm in thickness, the NH-L9 stands a mere 37mm tall, which makes it ideal for use in compact HTPCs or Small Form Factor cases that offer minimum clearance for CPU coolers.
  • The NH-L9i has a 95x95mm footprint that complies exactly to the Intel LGA115x socket keep-out zone. This means that it won’t cause issues with chipset coolers and doesn’t overhang the RAM slots, so it’s fully compatible with tall memory modules.
  • Most Intel LGA115x based mini-ITX mainboards have the PCIe slot sitting right next to 95x95mm socket zone. While larger coolers that exceed this zone are likely to block the PCIe slot, the 95x95xmm sized NH-L9i provides full compatibility with PCIe cards.
  • The highly optimized NF-A9x14 premium fan features Noctua’s proprietary AAO frame as well as sophisticated aerodynamic design measures. Supporting PWM for fully automatic speed control, the NF-A9x14 allows the NH-L9i to stay remarkably quiet.
  • Allowing to reduce the maximum speed of the NF-A9x14 fan from 2500 to 1800rpm, the included Low-Noise Adaptor (L.N.A.) makes it possible to achieve near-silent setups using CPUs with less than 65W TDP.
  • The NH-L9i bundles a custom-designed, back plate-less SecuFirm2 mounting system for LGA115x that offers extended compatibility with mini-ITX boards and makes installation easier than ever, all while maintaining the trusted SecuFirm2 quality.
  • 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.
    The specifications again underline the small footprint this thing has.


    * TDP Guide: they recommend a CPU that will have up to 65W of TDP.


Packaging and Visual Examination



Noctua does a great job detailing on the front the main attraction for each of their products. Here, the silver sticker informs us of the 37 mm total height. Then we have the key features that we saw earlier. And the fact that it is compatible with all Intel 115x sockets.


Flip it like a pancake and we have a quick description of the L9i in 8 languages. Then, on the right side down, there is a size representation of the cooler.


This side describes all the key specs for the heatsink, fan and all the accessories. But my eye is drawn to the 6 years manufacturer warranty offered and the fact that it is made in Taiwan.


Onto another side, we have the main features detailed.


I love when companies go the extra mile and take care of the unboxing experience. Noctua here did an excellent job in how they present the L9i.


Just look at that, like you bought a small piece of jewelry. The signed pamphlet on the top also enforces this idea.



We already know exactly what’s in the box.


– 1x NT-H1 thermal paste
– 1x Low-noise adapter (L.N.A.) – using this the NF-A9x14 fan’s speed is throttled to 1800 RPM in favor of quieter operation.
– 4x Motherboard securing bolts
– 4x Extra fan securing bolts (for a thicker fan if desired)
– 1x Noctua case badge
– 1x Installation manual (pamphlet)

Now the L9i. The “i” is for Intel sockets only. For AMD you need the “a” variant for this product. The fan is already pre-installed.


Here it is compared to the thinner version of the Intel stock cooler.




And here versus a Phanteks 140 mm fan.



The L9i is a perfect square at 95 by 95 mm. On this side we see the brand engraved. The some for the opposite plate.


The sides have the fins exposed and they are 0.44 mm thick with a 1.16 mm spacing. The back plate doesn’t have a perfect mirror finish.


Let’s remove the fan.


Now we can see that the NH-L9i is constructed like the rest of Noctua’s heatsinks, with a copper base and heatpipes, aluminum fins, soldered joints, and nickel-plating.


There are just two short 6 mm thick heatpipes but the cooler is quite dense, weighing 420 grams and the fins are very close to each other. This, combined with the top plates will help keep the fan’s pressure.



Speaking of the fan, it has the classic Noctua color combo, of light cream and bright brown. It is a 14mm-thick, 92mm NF-A9x14 PWM fan which is capable of up to 2500 RPM operational speed with an airflow rate of 57.5 m³/h and acoustic output of 23.6 dbA. Do notice the micro-dimples inside the fan frame that disturb the air, and even adding angled grooves in the blades lead to more air speed, pressure, and with less noise.


Now are you ready for one of the easiest CPU cooler installation experiences ever?




Take your motherboard. In our case, an mITX with vertical draughtboards, perfect to test the close quarter capability of the L9i cpu cooler.


Apply the thermal paste. Then attach the L9i.


Take the securing bolts – notice that they already have a plastic protection washer. Insert them from the back.
Screw them in.


Dead simple, no?

Ah and plug the fan in the CPU’s 4 pin header.


And to wrap things up, here are the tolerances. The L9i delivers what it promises.

Although at the limit, still zero interference and zero clearance problems with such a complicated motherboard.







Testing methodology


The CPU will be tested in 2 main scenarios: at stock settings and then overclocked at 4.5 Ghz with 1.280v, both scenarios with an Intel Burn Test run set at High stress settings, as the main torture test.

Room temperature set at ~ 20°C.

For the noise we used our Pyle PSPL01 placed 30 cm away from the setup.

Thermal paste used was the one that came with the Noctua NH-L9i.

We will compare the results to the Cryorig C7 (reviewed here) – a direct competitor to the L9i. Since the 6600k doesn’t come with any more Intel stock coolers, no need to include this one in the tests.

Both fans will be let on the auto % rpm curve and only for the noise test we will ramp them up to 100 %.

Any results over 90° C in any condition are considered a fail.

Let’s proceed.


Hardware used:

Processor: Intel i5 6600k @ OC’ed to 4.5 Ghz – 1.280v
Case: Ncase M1 V5.0 mITX
Motherboard: ASUS ROG Maximus Impact VII Z170 mITX
RAM: 16 GB (2×8) Corsair Vengeance LPX DDR4 2400 Mhz
GPU:Gigabyte GTX 1080 Founders Edition GDDR5X 8G
SSD: Samsung 850 Pro 256 GB
PSU: Corsair SF600W SFX w/ semi-fanless operation



– Windows 10 Pro x64 Build 1607
– NVIDIA GeForce WHQL 375.63
– Core Temp v1.7 R6 – To see the temperatures in real time
– CPU-Z v1.71 – To verify the CPU’s statistics
– Intel Burn Test v2.54 – Main torture and stability test
– MSI Afterburner v4.11 – To record the FPS and load/temperatures
– Valley Benchmark v1.0 – A popular testing suite

And for the games we did a 20 min run for each one and used games that are also CPU bound.
Resolution set at FHD / 1920 x 1080 with everything set to maximum quality settings and no V-sync.

– Witcher 3 v1.21
– Rise Of The Tomb Raider (DX12)

Ok then.




Here are some validation screens:


A run in the Valley benchmark:


The temperatures in Intel Burn test:


The mixed gaming temperatures:


And the acoustics testing:





Even though the C7 has a bigger heatsink, the fan is not as good as the Noctua’s and this clearly shows and on the auto profile fan curve when it looses to the Noctua in the games tests. But while it ramps up at the cost of very high noise, the C7 is slightly better performing than the Noctua.

The Noctua is a great performer overall and has the quieter fan, minus the max % where all coolers are noisy.




Even though they recommend to use a CPU with a thermal design output up to 65W, in our testing the L9i had no problems handling the 6600k, an enthusiast class CPU in both stock and even overclocked scenarios, despite the fact that the Cryorig C7 has the official 91W TDP rating.

The Noctua NH-L9i takes the crown for now for the best overall all-arounder very low profile cooler.

The good:

+ Superb built quality and finish
+ Surprisingly good cooling capability
+ Really quiet operation
+ 6 years warranty
+ Zero clearance problems
+ Very easy installation experience
+ Perfect product description and presentation

The bad:

– You need a separate version of this cooler altogether for the AMD platform
– The color scheme not to everybody’s liking


Glob3trotters “The best SFF Cooler” Award – 4.5 out 5


Join the discussion 2 Comments

  • Iftekhar says:

    I personally use Noctua NH-L9i and this is a fantastic cooler. However, this cooler tend to bend the motherboard even if you tighten up the screws at the back by a small margin. Though they are fairly smaller in size, I honestly think a supporting back-plate would have been much nicer. Apart from that, this is very good cooler for smaller cases with CPU TDP 65W or lower. Definitely not suitable for OC. Thanks.

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