Noctua NH-L9i CPU Cooler Review
By Rafael Coelho on January 7, 2013


The Noctua NH-L9i is a low-profile CPU cooler that is only 1.46” (37 mm) tall and uses a 92 mm PWM fan. Let’s test it!

The NH-L9i comes in a small cardboard box, as seen in Figure 1.

Noctua NH-L9i
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Figure 1: Package

Figure 2 shows the contents of the box: the cooler itself, a tube of thermal compound, manual, a power adapter, a case badge, and four screws. The accessories come nicely fitted in a foam layer.

Noctua NH-L9i
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Figure 2: Accessories

Figure 3 displays the Noctua NH-L9i.

Noctua NH-L9i
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Figure 3: The Noctua NH-L9i

This cooler is discussed in detail in the following pages.

The Noctua NH-L9i

Figure 4 illustrates the front of the cooler, where you can see how thin (0.9” or 23 mm) the heatsink is, and the fan (0.55” or 14 mm). You can also see the tips of the two heatpipes.

Noctua NH-L9i
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Figure 4: Front view

Figure 5 reveals the rear of the cooler.

Noctua NH-L9i
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Figure 5: Rear view

In Figure 6, you can see the side of the cooler.

Noctua NH-L9i
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Figure 6: Side view

Figure 7 shows the top of the cooler, completely covered by the 92 mm fan.

Noctua NH-L9i
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Figure 7: Top view

The Noctua NH-L9i (Cont’d)

Figure 8 illustrates the bottom of the cooler. The nickel-plated copper base is very well polished.

Noctua NH-L9i
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Figure 8: Bottom view

Figure 9 reveals the heatsink with the fan removed.

Noctua NH-L9i
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Figure 9: Heatsink

The 92 mm PWM fan that comes with the NH-L9i is shown in Figure 10. The cooler is also compatible with thicker (1” or 25 mm) 92 mm fans.

Noctua NH-L9i
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Figure 10: Fan


The installation of the Noctua NH-L9i is very simple. Just put the cooler over the CPU, insert and screw the four screws from the solder side of the motherboard, as shown in Figure 11.

Noctua NH-L9i
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Figure 11: Screws on the solder side

Figure 12 shows the NH-L9i installed in our computer.

Noctua NH-L9i
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Figure 12: Cooler installed

How We Tested

We tested the cooler with a Core i5-2500K CPU (quad-core, 3.3 GHz), which is a socket LGA1155 processor with a 95 W TDP (Thermal Design Power). In order to get higher thermal dissipation, we overclocked it to 4.0 GHz (100 MHz base clock and x40 multiplier), with 1.3 V core voltage (Vcore). This CPU was able to reach 4.8 GHz with its default core voltage, but at this setting, the processor enters thermal throttling when using mainstream coolers, reducing the clock and thus the thermal dissipation. This could interfere with the temperature readings, so we chose to maintain a moderate overclocking.

We measured noise and temperature with the CPU under full load. In order to get 100% CPU usage in all cores, we ran Prime 95 25.11 with the “In-place Large FFTs” option. (In this version, the software uses all available threads.)

We compared the tested cooler to other coolers we already tested, and to the stock cooler that comes with the Core i5-2500K CPU. Note that the results cannot be compared to measures taken on a different hardware configuration, so we retested some “old” coolers with this new methodology. This means you can find different values in older reviews than the values you will read on the next page. Every cooler was tested with the thermal compound that comes with it.

Room temperature measurements were taken with a digital thermometer. The core temperature was read with the SpeedFan program (available from the CPU thermal sensors), using an arithmetic average of the core temperature readings.

During the tests, the panels of the computer case were closed. The front and rear case fans were spinning at minimum speed in order to simulate the “normal” cooler use on a well-ventilated case. We assume that is the common setup used by a cooling enthusiast or overclocker.

The sound pressure level (SPL) was measured with a digital noise meter, with its sensor placed near the top opening of the case. This measurement is only for comparison purposes, because a precise SPL measurement needs to be made inside an acoustically insulated room with no other noise sources, which is not the case here.

Hardware Configuration

Operating System Configuration

Software Used

Error Margin

We adopted a 2°C error margin, meaning temperature differences below 2°C are considered irrelevant.

Our Tests

The table below presents the results of our measurements. We repeated the same test on all coolers listed below. Each measurement was taken with the CPU at full load. In the models with a fan supporting PWM, the motherboard controlled the fan speed according to core load and temperature. On coolers with an integrated fan controller, the fan was set at the full speed.

CoolerRoom Temp.NoiseSpeedCore Temp.Temp. Diff.
Cooler Master Hyper TX318 °C50 dBA2850 rpm69 °C51 °C
Corsair A7023 °C51 dBA2000 rpm66 °C43 °C
Corsair H10026 °C62 dBA2000 rpm64 °C38 °C
EVGA Superclock26 °C57 dBA2550 rpm67 °C41 °C
NZXT HAVIK 14020 °C46 dBA 1250 rpm65 °C45 °C
Thermalright True Spirit 12026 °C42 dBA1500 rpm82 °C56 °C
Zalman CNPS12X26 °C43 dBA1200 rpm71 °C45 °C
Zalman CNPS9900 Max20 °C51 dBA1700 rpm62 °C42 °C
Titan Fenrir Siberia Edition22 °C50 dBA2400 rpm65 °C43 °C
SilenX EFZ-120HA518 °C44 dBA1500 rpm70 °C52 °C
Noctua NH-L1220 °C44 dBA1450 rpm70 °C50 °C
Zalman CNPS8900 Extreme21 °C53 dBA2550 rpm71 °C50 °C
Gamer Storm Assassin15 °C48 dBA1450 rpm58 °C43 °C
Deepcool Gammaxx 40015 °C44 dBA1500 rpm60 °C45 °C
Cooler Master TPC 81223 °C51 dBA2350 rpm66 °C43 °C
Deepcool Gammaxx 30018 °C43 dBA1650 rpm74 °C56 °C
Intel stock cooler18 °C41 dBA2000 rpm97 °C79 °C
Xigmatek Praeton19 °C52 dBA2900 rpm83 °C64 °C
Noctua NH-U12P SE218 °C42 dBA1300 rpm69 °C51 °C
Deepcool Frostwin24 °C46 dBA1650 rpm78 °C54 °C
Thermaltake Frio Advanced13 °C56 dBA2000 rpm62 °C49 °C
Xigmatek Dark Knight Night Hawk Edition9 °C48 dBA2100 rpm53 °C44 °C
Thermaltake Frio Extreme21 °C53 dBA1750 rpm59 °C38 °C
Noctua NH-U9B SE212 °C44 dBA1700 rpm64 °C52 °C
Thermaltake WATER2.0 Pro15 °C54 dBA2000 rpm52 °C37 °C
Deepcool Fiend Shark18 °C45 dBA1500 rpm74 °C56 °C
Arctic Freezer i3013 °C42 dBA1350 rpm63 °C50 °C
Spire TME III8 °C46 dBA1700 rpm70 °C62 °C
Thermaltake WATER2.0 Performer11 °C54 dBA2000 rpm49 °C38 °C
Arctic Alpine 11 PLUS11 °C45 dBA2000 rpm82 °C71 °C
be quiet! Dark Rock 210 °C41 dBA1300 rpm58 °C48 °C
Phanteks PH-TC14CS16 °C47 dBA1300 rpm58 °C42 °C
Phanteks PH-TC14PE16 °C48 dBA1300 rpm57 °C41 °C
SilverStone HE01 (Q)19 °C44 dBA1150 rpm63 °C44 °C
SilverStone HE01 (P)20 °C57 dBA2050 rpm62 °C42 °C
Thermaltake WATER2.0 Extreme (S)17 °C44 dBA1250 rpm52 °C35 °C
Thermaltake WATER2.0 Extreme (E)17 °C53 dBA1900 rpm50 °C33 °C
Deepcool Neptwin11 °C46 dBA1500 rpm56 °C45 °C
SilverStone HE0219 °C49 dBA2000 rpm64 °C45 °C
Zalman CNPS9900DF23 °C45 dBA1400 rpm68 °C45 °C
Deepcool ICE BLADE PRO V2.022 °C43 dBA1500 rpm67 °C45 °C
Phanteks PH-TC90LS24 °C47 dBA2600 rpm95 °C71 °C
Rosewill AIOLOS20 °C40 dBA1600 rpm94 °C74 °C
Corsair H6020 °C49 dBA2000 rpm64 °C44 °C
Zalman LQ31027 °C51 dBA2050 rpm65 °C38 °C
Noctua NH-L9i24 °C44 dBA2500 rpm95 °C71 °C

In the graph below, you can see how many degrees Celsius hotter the CPU core is than the air outside the case. The lower this difference, the better is the performance of the cooler.

Noctua NH-L9i

In the graph below, you can see how many decibels of noise each cooler makes.

Noctua NH-L9i

Main Specifications

The main specifications for the Noctua NH-L9i CPU cooler include:

* Researched at on the day we published this review.


The Noctua NH-L9i is a very well-made, low-profile CPU cooler, with the same construction quality we are accustomed to seeing in other coolers from this manufacturer.

However, there is no point in comparing the cooling performance of such a low-profile cooler to the high-end tower coolers. Therefore, we must pay attention to the data comparing the portrayed cooler to the stock cooler and other low-profile models.

The NH-L9i is shorter than the Xigmatek Praeton, the Phanteks PH-TC90LS, and the stock cooler. It performed better than the stock cooler, had a performance equivalent to the PH-TC90LS’s, but presented worse performance than the Praeton. It was, however, quieter than those retail coolers, being almost as silent as the stock cooler.

So, if you are building a PC (or an HTPC) in an SFF case and looking for a really low-profile and quiet cooler with better performance than the stock cooler, the Noctua NH-L9i is a product to consider.

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