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Noctua NH-L9i Low Profile CPU Cooler

The Noctua NH-L9i is a high-end miniature CPU heatsink designed with compatibility first and foremost in mind. Measuring just 95 mm x 95 mm across and standing 37 mm tall, it fits in the vast majority of low profile SFF cases.

November 22, 2012 by Lawrence Lee

Product
Noctua NH-L9i
LGA1155/1156
CPU Cooler
Manufacturer
Noctua
Street Price
US$45~US$50

Designing a small CPU cooler is a difficult task in this day and age. Height is the main issue as there is no universally accepted heatsink clearance limit for small form factor cases, not that SFF is a standard in itself either. Taller heatsinks offer better performance at the cost of compatibility, while smaller, less capable models have to employ higher fan speeds to make up the difference. Complicating matters is the popularity of Intel mini-ITX motherboards for LGA1155/1156, most of which are laid out with the PCI Express 16x slot very close to the best CPU socket, making heatsink length and width an issue as well.

Noctua dipped their toe into the small cooler market with the NH-L12, a miniaturized version of the NH-C14. For its size, it delivered exceptional performance in both its two fan (93 mm tall) and one fan (66 mm tall) configurations. Unfortunately it suffers from the size issues we just mentioned, being too tall for smaller enclosures and having a large footprint causing PCI Express slot interference in many mini-ITX boards. Noctua’s second entry, the NH-L9i, takes a very different approach, focusing on compatibility above all else.


The NH-L9i.

The NH-L9i, is essentially, the lowest common denominator of small CPU heatsinks. It’s length and width are 95 mm, strictly within the specified area Intel allows for OEM coolers, meaning it does not interfere with memory slots, VRM heatsinks, or anything else. It’s also incredibly slim, only 37 mm tall, which means it actually sits lower on the board that a typical set of DDR3 DIMMs with heatspreaders, so it’s effectively compatible with any case that can take standard desktop mini-ITX mainboard.

It’s a fairly simply heatsink design with a pair of copper heatpipes entwined in a dense array of aluminum fins. Sitting atop the fin mass is a new style of Noctua fan, a slim 92 mm model with shallow ridges on the top edge of each fan blade. The fan is also screwed on rather than utilizing clips which would have increased its physical dimensions.


The NH-L9i box and contents.

The NH-L9i is designed for LGA1155/1156 only so there isn’t much mounting gear included, just a set of thumbscrews for installing the heatsink and a set of longer bolts if you want to swap out the 14 mm thick fan with a standard 25 mm model. Noctua also offers an AMD version of the heatsink, the NH-L9a, which is actually physically longer as it conforms to AMD’s rectangular socket shape. The accessories include a low noise fan adapter, a metallic case badge, and a tube of thermal compound.

Noctua NH-L9i: Key Features
(from the product
web page
)
Feature & Brief
Our Comment
37mm low profile
Due to the slim 23mm heatsink 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.
There is no clear definition of “low profile” but at 37 mm, it should fit in most consumer SFF cases that described as such.
100% RAM compatibility
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.
To be fair, most heatsinks that extend over the memory slots don’t interfere with standard height DIMMs.
100% compatibility with PCIe cards on mini-ITX
Most Intel LGA115x based mini-ITX mainboards have the PCIe slot sitting right next to the 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.
Most Sandy/Ivy Bridge mini-ITX boards have the PCI-E 16x slot so close to the socket that most aftermarket coolers won’t fit with a graphics card installed.
NF-A9x14 PWM premium fan
The highly optimised 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.
After sticking with the same basic fan design for several years, we were surprised they changed it up the fan on the NH-L12 heatsink. Now they’ve done it again on the NH-L9i’s fan, a thin 92 mm model.
Low-Noise Adaptor
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.
In the olden days, Noctua included both a 7V and 9V adapter for those without motherboard fan control. With PWM control being so universal, an adapter is purely an accessory.
Custom-designed SecuFirm2™ mounting for LGA115x
The NH-L9i bundles a custom-designed, backplate-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.
Though it carries the same name, the NH-L9i’s mounting system doesn’t resemble the SecuFirm2 kit of their larger coolers.

 

Noctua NH-L9i: Specifications
(from the product
web page
)
Socket compatibility LGA1150, LGA1155, LGA1156
Height (without fan) 37 mm (23 mm)
Width 95 mm
Depth 95 mm
Weight (without fan) 420 g (345 g)
Material Copper (base and heat-pipes), aluminum (cooling fins), soldered joints & nickel plating
Fan compatibility 92x92x14mm, 92x92x25mm
Scope of Delivery * NF-A9x14 PWM premium fan
* Low-Noise Adaptor (L.N.A.)
* NT-H1 high-grade thermal compound
* SecuFirm2™ Mounting Kit
* Screws for 92x92x25mm fans
* Noctua Metal Case-Badge
Warranty 6 Years
Fan Specifications
Model Noctua NF-A9x14 PWM
Bearing SSO2
Max. Rotational Speed 2500 RPM
Max. Rotational Speed with L.N.A. (+/- 10%) 1800 RPM
Min. Rotational Speed (PWM) 300 RPM
Max. Airflow 57,5 m³/h
Max. Airflow with L.N.A. 40,8 m³/h
Max. Acoustical Noise 23,6 dB(A)
Max. Acoustical Noise with L.N.A. 14,8 dB(A)
Input Power 2,52 W
Voltage Range 12 V
MTBF > 150.000 h

PHYSICAL DETAILS & INSTALLATION

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. The dimensions are tiny, 95 x 95 x 37 mm or 3.7 x 3.7 x 1.5 inches (L x W x H) and there are just two short 6 mm thick heatpipes. However, this diminutive cooler is quite dense, weighing 420 grams or about 0.93 lb.


Noctua jammed 55 fins into the NH-L9i, making it the most tightly-spaced heatsink in their lineup. Each fin is approximately 0.44 mm thick and spaced only 1.16 mm apart on average.


As the NH-L9i has limited socket compatibility, the one set of included mounting clips is pre-installed for your convenience. The base is very flat with a well-machined surface.


The installation procedure is dead simple. Apply thermal compound to the CPU heatspreader, flip the heatsink upside down, lay the board on top of the heatsink and secure four thumbscrews at the back.


At 37 mm, it’s no taller than an average set of RAM and barely extends beyond the outline of the CPU socket.


On our test board, it barely cleared some capacitors around the socket.


We were a bit surprised to see poor contact between the base and CPU heatspreader on a Noctua cooler. The omission of their famous universal mounting kit might be the source of the problem.

TESTING

Before thermal testing, we took some basic physical measurements.

Approximate Physical Measurements
Weight
350 g
420 g with stock fan
Height 37 mm with stock fan
Fin count 55
Fin thickness
0.44 mm
Fin spacing
1.16 mm
Vertical Clearance*
N/A
* measured from the motherboard PCB to
the bottom fin of the heatsink.

 

Small Heatsink Comparison:
Average Fin Thickness & Spacing
Heatsink
Fin Thickness
Fin Spacing
Scythe Big Shuriken 2 Rev.B
0.29 mm
1.13 mm
Noctua NH-L9i
0.44 mm
1.16 mm
Scythe Big Shuriken
0.33 mm
1.19 mm
Reeven Vanxie
0.28 mm
1.39 mm
Reeven Arcziel
0.28 mm
1.41 mm
Cooler Master GeminII M4
0.29 mm
1.46 mm
Noctua NH-L12
0.49 mm
1.51 mm
Scythe Kozuti
0.12 mm
1.69 mm
Scythe Samurai ZZ
0.33 mm
1.74 mm
Prolimatech Panther
0.53 mm
1.80 mm

Testing on larger heatsinks are done on our
LGA1366 heatsink testing platform
, while smaller coolers tackle our LGA1155 heatsink testing platform. A summary of the test system
and procedure follows.

Key Components in LGA1366 Heatsink Test Platform:

Key Components in LGA1155 Heatsink Test Platform:

The systems are silent under the test conditions, except for the CPU cooling
fan(s).

Normally, our reference fans are used whenever possible, the measured details
of which are shown below.

Reference Noctua 140mm fan
Anechoic chamber measurements
Voltage
SPL@1m
Speed
12V
28~29 dBA
1250 RPM
9V
21 dBA
990 RPM
8V
18 dBA
880 RPM
7V
15~16 dBA
770 RPM
6V
13 dBA
660 RPM

 

Reference Nexus 120mm fan
Anechoic chamber measurements
Voltage
SPL@1m
Speed
12V
16 dBA
1080 RPM
9V
13 dBA
880 RPM
7V
12 dBA
720 RPM

 

Reference Nexus 92 mm fan
Anechoic chamber measurements
Voltage
SPL@1m
Speed
12V
16 dBA
1470 RPM
9V
12 dBA
1150 RPM

Measurement and Analysis Tools

  • Extech 380803 AC power analyzer / data logger for measuring AC system
    power.
  • Custom-built, four-channel variable DC power supply, used to regulate
    the fan speed during the test.
  • PC-based spectrum analyzer:
    SpectraPlus with ACO Pacific mic and M-Audio digital
    audio interfaces.
  • Anechoic chamber
    with ambient level of 11 dBA or lower
  • Various other tools for testing fans, as documented in our
    standard fan testing methodology
    .
  • SpeedFan,
    used to monitor the on-chip thermal sensors. The sensors are not calibrated,
    so results are not universally applicable. The hottest core reading is used.
  • Prime95,
    used to stress the LGA1366 CPU heavily, generating more heat than most real applications.
    8 instances are used to ensure that all 4 cores (with Hyper-threading) are
    stressed.
  • CPU-Z,used to monitor the CPU speed to determine when overheating occurs.
  • Thermometers to measure the air temperature around the test platform
    and near the intake of the heatsink fan.

Noise measurements are made with the fans powered from the lab’s variable DC
power supply while the rest of the system was off to ensure that system noise
did not skew the measurements.

Load testing was accomplished using Prime95 to stress the processor and the
graph function in SpeedFan was used to ensure that the load temperature is stable
for at least ten minutes. The temperature recorded is the highest single core
reading. The stock fans were tested at various voltages to represent a good
cross-section of airflow and noise performance.

The ambient conditions during testing were 10~11 dBA and 21~23°C.

Stock Fan Measurements

Specifications: Noctua NH-L9i
Manufacturer
Power Rating
2.52 W
Model Number
NF-A9x14 PWM
Airflow Rating
40.8 ~ 57.5 m³/h
Bearing Type
SSO2
Speed Rating
300 ~ 2500 RPM
Corners
Closed
Noise Rating
14.8 ~ 23.6 dBA
Frame Size
92 x 92 x 14 mm
Header Type
4-pin
Blade Diameter
86 mm
Starting Voltage
4.3 V
Hub Size
33 mm
Weight
70 g
Data in green cells provided by the manufacturer
or observed; data in the blue cells were measured.

The NH-L9i sports a thin 92 mm fan with a rotational speed of 2500 RPM and a very short, 20 cm 4-pin cable. It’s from a new generation of Noctua fans that look nothing like the previous models aside from the color scheme. Noticeably absent are their famous “vortex control notches” on the struts and blades, though there are a few ridges on the intake side. Furthermore, the blade corners are more rounded, giving it a classic torpedo style design.

The 92 mm stock fan had excellent acoustics, producing a very smooth profile. Aside from turbulence at higher speeds, the sound generated was pleasant throughout the range we tested and we didn’t perceive any tonality. It’s a vast improvement over mismatched fans of the larger NH-L12.

Stock Fan Measurements
Voltage
Speed
SPL@1m
12V
2430 RPM
34 dBA
9V
2020 RPM
28 dBA
7V
1710 RPM
22 dBA
6V
1530 RPM
18 dBA
5V
1330 RPM
15 dBA
Measuring mic positioned 1m at diagonal angle from
the center of the heatsink.
Ambient noise level: 10~11 dBA.

The fan reacted quite linearly on voltage control, peaking at 34 dBA@1m at top speed speed and dipping down to a very quiet 15 dBA@1m at 5V. The starting voltage of the fan was only 4.3 V so we didn’t see cause to push it any lower. With the fan running at the nominal 12V, the included low noise adapter brought the speed down to about 1800 RPM which is equivalent to approximately 8V. However, with PWM control you can make it effectively inaudible so it really isn’t necessary in most cases.

Test Results

Noctua NH-L9i
Fan Voltage
Fan Speed
SPL@1m
°C Rise above Ambient
CPU
VRM
RAM
Stock Fan
12V
2430 RPM
34 dBA
46
26
20
9V
2020 RPM
28 dBA
51
32
26
7V
1710 RPM
22 dBA
54
37
28
6V
1530 RPM
18 dBA
56
40
30
5V
1330 RPM
15 dBA
61
46
32
Reference Nexus 92mm Fan
12V
1420 RPM
19~20 dBA
55
38
26
9V
1150 RPM
14 dBA
63
48
32

For such a short heatsink, simply surviving our test without our overclocked/overvolted CPU throttling is in accomplishment. The NH-L9i performed fairly well, staying 20°C below the throttling point at the lowest tested speed. The fan became what we consider quiet between 1700 and 1500 RPM which is fairly close to the performance sweet spot. Surprisingly when we strapped on our thicker Nexus 92 mm reference fan, we didn’t see any improvement.

Heatsink Comparison Table

°C rise Comparison (CPU Temperature)
SPL (dBA@1m)
20
19
18
17
16
15
14
13
12
Noctua NH-L12
(both fans)
33
34
35
36
Noctua NH-L12
(120mm fan)
37
38
39
42
Prolimatech Panther
35
42
Scythe Big Shuriken 2 Rev.B
39
43
48
Reeven Arcziel
42
47
Scythe Samurai ZZ
45
46
52
Noctua NH-L12
(92mm fan)
42
44
47
51
57
Scythe Big Shuriken
43
46
61
Cooler Master GeminII M4
53
56
64
Noctua NH-L9i
56
61
Noctua NH-L9i
(ref. 92 mm fan)
55
63
Scythe Kozuti
57
62
65
Reeven Vanxie
66
77
F

Given its size, the NH-L9i was easily dominated by most of the heatsinks we’ve tested in the past. But compared to coolers with similar size profiles, the NH-L9i came out on top, albeit just barely — the Scythe Kozuti came within one degree. The Kozuti is slightly taller at 40 mm but it weighs about 40% less and it’s paired with a smaller fan as well.

°C rise Comparison (VRM Temperature)
SPL (dBA@1m)
20
19
18
17
16
15
14
13
12
Noctua NH-L12
(both fans)
17
19
21
23
Prolimatech Panther
24
30
Noctua NH-L12
(120mm fan)
24
26
27
32
Scythe Big Shuriken 2 Rev.B
29
34
39
Noctua NH-L12
(92mm fan)
28
31
33
38
43
Reeven Arcziel
38
41
Scythe Big Shuriken
28
30
47
Cooler Master GeminII M4
34
38
49
Scythe Kozuti
36
40
45
Scythe Samurai ZZ
38
39
47
Noctua NH-L9i
40
46
Noctua NH-L9i
(ref. 92 mm fan)
38
48
Reeven Vanxie
45
56
F

For VRM cooling, the Kozuti was actually superior, probably because its fan
is closer to the board components while the NH-L9i’s fan has to blow through
a dense pack of fins.

MP3 SOUND RECORDINGS

These recordings were made with a high
resolution, lab quality, digital recording system
inside SPCR’s
own 11 dBA ambient anechoic chamber
, then converted to LAME 128kbps
encoded MP3s. We’ve listened long and hard to ensure there is no audible degradation
from the original WAV files to these MP3s. They represent a quick snapshot of
what we heard during the review.

These recordings are intended to give you an idea of how the product sounds
in actual use — one meter is a reasonable typical distance between a computer
or computer component and your ear. The recording contains stretches of ambient
noise that you can use to judge the relative loudness of the subject. Be aware
that very quiet subjects may not be audible — if we couldn’t hear it from
one meter, chances are we couldn’t record it either!

The recording starts with 5~10 second segments of room ambiance, then the fan
at various levels. For the most realistic results, set the volume so that
the starting ambient level is just barely audible, then don’t change the volume
setting again.

FINAL THOUGHTS

Naturally, the Noctua NH-L9i can’t compare to some of the larger CPU coolers on the market. Against the Noctua NH-L12, arguably the premiere small heatsink, you can expect a hit of 15~20°C and that’s with the NH-L12 in its shorter 66 mm tall, single 120 mm fan configuration. When you take into account that the NH-L9i is a mere 37 mm tall, its performance seems rather impressive. Additionally, unlike the NH-L12 and Scythe Big Shuriken 2, it doesn’t interfere with the PCI-E 16x slot on most Intel LGA1155 mini-ITX motherboards.

In a vacuum, the NH-L9i would be the choice for an ultra-slim mini-ITX build, but sadly for Noctua and lucky for us, it has a very strong competitor in the Scythe Kozuti. The Kozuti trailed the NH-L9i by a negligible amount on our test platform despite having a smaller fan and a much lighter build. Scythe designed their low profile cooler with a fan right over the base where it makes the most difference and maximizing the heat dissipation area by using very thin fins. Noctua on the other hand, used a larger fan blowing down on densely packed and very thick nickel-plated fins (which undoubtedly impedes airflow). Its cooling potential was also limited by the NH-L9i’s mounting system which also isn’t up to Noctua’s usual standards, creating less than ideal contact with the CPU heatspreader.

The NH-L9i primary advantage lies in its acoustics — its fan sounds incredibly
smooth compared to the more buzzy Scythe model — and its virtually guaranteed
fit on any LGA1155 board, including mini-ITX, without interfering with any components
or addons. The NH-L9i is 3 mm shorter, and it does not extend out beyond the
“no fly zone” area dedicated for the heatsink. In contrast, the top
portion of the Kozuti fin bank extends out farther, and on some mini-ITX boards,
it can interfere with tall RAM heatspreaders and the card in the PCIe slot.
The Kozuti is just big enough that it will not work on some Zotac mini-ITX boards
with big VRM heatsinks, for example, and the spacing between the edge of the
finstack and the video card is always very small, tight enough that you’d be
wise to insert a thin insulator of some kind in case of accidental contact.

You can also swap the NH-L9i’s fan with a thicker model, though doing with
our reference fan didn’t result in any improvement in our tests. It’s
up to you whether the superior acoustics and assured pysical compatibility justifies
the NH-L9i’s US$10 ~$15 price premium over the Kozuti. Like most small
heatsinks though, both are rather expensive for the amount of materials involved
— that’s just the price you have to pay for niche products.

Our thanks to Noctua for the NH-L9i CPU cooler sample.

* * *


Noctua NH-L9i is Recommended by SPCR

SPCR Articles of Related Interest:

Zalman CNPS9900DF Dual Fan Flower Heatsink
Prolimatech MK-26 Multi-VGA Cooler
SilverStone Heligon HE02: Monster Fanless CPU Cooler
Prolimatech Panther CPU Cooler
Phanteks PH-TC14PE Dual Fan CPU Heatsink
GELID GX-7 & Tranquillo Rev.2 CPU Coolers

* * *

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