Noctua NH-L9i Low-Profile CPU Cooler Review

Noctua delivers the ultimate CPU cooling solution for those with serious clearance issues in their compact SFF PC build.

Manufacturer: Noctua
12 minutes & 40 seconds read time


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For those who don't know who Noctua is, I kindly ask that you take a peek from under your rock a bit more often. Noctua has been on the edge of cooler design long before I got my humble start reviewing them. With my first glance at some of the older tower coolers, I wasn't quite sure what it was that made them so good, but then I grabbed it and could instantly feel that there was a more professional grade feel to the cooler. Then I was told to connect it up to the PC and spin it up. At this point I stood in amazement from the lack of volume coming from inside the PC while I looked at a screen in disbelief of the thermal results.

Since that time Noctua may no longer be the only silent offering out there, but they have kept their heads in the game and are always looking for new or better ways to innovate coolers. Whether we are discussing the D-14 behemoth, or even some of the C-Style coolers, Noctua has been delivering top-end performance even when the coolers had to be limited in size. On that note, Noctua has now developed one of the smallest coolers I have ever tested, and that includes low profile Intel stockers, and that SilverStone cooler that was essentially the same thing. Knowing Noctua as I do, and knowing they wouldn't just send out a cooler that was small enough to fit, but didn't have the ability to control the heat. While there is a strict set of TDP guidelines, if followed correctly, this new cooler will have no issues cooling your processors where most other larger coolers have no chance to.

The CPU cooler I am looking at today from Noctua is one of a pair of coolers. There is the NH-L9a for AMD processors, and there is the NH-L9i for Intel processors that we received. In this design you not only are going to be getting a very compact and short set of fins, but you will also be using a 14mm thick 92mm fan to do the cooling.

Right off the bat you can tell this isn't a cooler for extreme overclockers, but for those with the need to use as little CPU cooler as possible to tame the heat inside of an HTPC or some other SFF chassis, I strongly urge you to continue reading as the NH-L9i is impressive for its super compact size.

Specifications, Availability and Pricing

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The NH-L9i starts with a copper base plate which is attached to a pair of 6mm diameter heat pipes. Then a very short stack of aluminum fins, 55 in total, are soldered to the heat pipes for maximum heat transfer and then the entire assembly is nickel plated. This version of the cooler only fits the LGA1155 and LGA1156 for now, along with upcoming LGA1150 CPUs. The NH-L9i stands 23mm tall without the fan and only 37mm with it installed. From side to side, or top to bottom, the NH-L9i is square with a 95mm measurement in both directions. What is also nice is that the combined weight of this cooler is only 420 grams, lessening the strain on the CPU socket.

The fan that comes along for the ride with the NH-L9i is the NF-A9x14 PWM fan. This is a 92mm wide and tall fan that is 14mm thick. Sticking with the SSO2 bearing in the hub, this 92mm fan can spin up to 2500RPM delivering 57.5m3/h of air flow. There is an L.N.A. adapter included that will take the RPMs down to 1800 and the airflow also drops to 40.8m3/h. The use of the L.N.A. adapter has its limits, though. While this cooler can handle 95W CPUs with really good case air flow helping it out, Noctua recommends you don't use the L.N.A. for those. For 77W CPUs or 65W offerings you can use it, but again I still advise there is good air flow in the chassis. That being said, there is only 9 dB difference between using it or not, and even on the high-end we are dealing with 23 dB without it in line.

Even though this cooler has been in the news for quite some time already, availability on this side of the pond is quite limited. I was able to locate the NH-L9i at Newegg at a reasonable price too, but they only show stock of the AMD version currently. If you need the NH-L9i for one of your builds, you are going to have to deal with a couple of odd stores I have never dealt with. First there is Quiet PC USA selling it at $45.95, and the only other place I could find stock was at $46.50. Both locations have shipping to incorporate on top of that pricing.

Considering there is only one other cooler that can fit in the same places as the NH-L9i and that would be the $30 offering from Phanteks in the PH-TC90LS which did all right, but not great, and there wasn't the ability to change the fan like there is with the Noctua solution.


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Looking at the top of the box for the NH-L9i you can see on the left that this cooler fits all of the LGA 115x CPUs and under the text explaining this is a low profile cooler with the chromed sticker showing only 37mm tall, you also get six bullet points on the features of this cooler.

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On the smaller end at the right of the box you now get images and text to cover other features. First is the 37mm height, then the NF-A9x14 PWM fan, the memory compatibility, the custom SecuFirm2 mounting, the fact it won't block PCI-e slots, and that there is supplied NT-H1 compound.

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The opposite panel is black like this, but is blank. On the back there are some bar codes along with the name and that this is an L-Type low-profile cooler.

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The last of the side panels offers both the fan and heatsink specifications on the left of the tick blue stripe. To the right of it there is another chart that covers the scope of delivery, or what is included in the box.

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Under the box you can also find more information. Here Noctua starts off with what makes up the NH-L9i and why you would need one. This gets repeated in seven other languages, and then on the right, you get some dimensional renderings of the cooler.

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The inner packaging consists of a layer of cardboard that holds the cooler in place, and allows for a place for the layer of high density foam to rest on. You can see everything that is included with just a glance except for a set of screws, but I loved the presentation as the lid got lifted.

Noctua NH-L9i Low-Profile CPU Cooler

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I wanted to start off by looking down inside of the 92mm fan and show you not only the traditional colors of Noctua, but also to show how compact the NH-L9i is from the top. This is how Noctua knows you won't have issues with memory or a video card, this thing is only slightly larger in its footprint than a stock cooler.

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The cooler comes completely assembled from the mounting legs at the bottom, on through the heavy fan mounting plate screwed to the side with the Noctua name on it, right on into the fan, you are really only four screws and a ran connection from use at this point.

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The side of the cooler shows how snug the 55 aluminum fins are packed together. Even with such little spacing, Noctua still took steps to make sure to fold over the edges for both structural support as well as spacing support; you don't want these fins all packing up together.

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At this end you can not only see the wiring for the 4-pin PWM connector to power the fan, but you can see the termination of the two 6mm diameter heat pipes as they exit the side of the cooler and the thicker metal end used to support the fan that gets screwed on to this side as well.

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This side is a dead match to its opposing side. In reality, the folded over edges of the fins is just a secondary measure to keep the spacing correct. Since the fins are directly soldered to the heat pipes, the spacing is going to stay pretty even anyways.

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As I mentioned, everything comes ready to go with the NH-L9i, even the mounting legs are already on the bottom and screwed into place. Protecting the base of the cooler is a thick plastic that has been applied to keep the finish just as it left the factory.

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The base of the NH-L9i is very flat across the entire surface and the base is much larger than the IHS so the height of the mounting legs is not an issue. If you look closely you can see grooves arches across the base, as Noctua likes more surface area for the TIM over a mirror polished finish to get the job done.

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The mounting legs are offset at the end to allow for the appropriate socket height and are simply drilled and tapped to accept the threads from the screws that go in from behind the motherboard.

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I went ahead and removed the fan so that you had a chance to see in between all of these fins. You can see there is a wide strip of metal that goes from right to left that has the base on one side and the U-shaped heat pipes soldered to it. You can also now see the fan mounting holes that are bent over bits of the side panels.

Accessories and Documentation

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The hardware and goodies included are seen here. You get a set of four longer screws for if you want to use a 25mm thick fan instead. You also get the L.N.A. adapter, a tube of NT-H1, four screws with nylon washers on them to mount the cooler, and the metal Noctua case badge.

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Unfolding the paperwork that was tucked into the back of the lid in the box, you can see there are only four steps to installing the NH-L9i. Add some TIM to the CPU, place the cooler, insert the screws and tighten them down, then plug in the fan; it really doesn't get much easier.

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I also wanted to show off the NF-A9x14 PWM fan. Since my last look at fans like these, I see the isolation rubber near the screw holes is much smaller, but other features of the fan stay the same.

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Not only the blade shape and amount make for a good fan and Noctua knows this. This is why they engineered step downs on the intake edge of the fan, use the micro-dimples inside the fan frame to disturb the air, and even adding angled grooves in the blades lead to more air speed, pressure, and with less noise.

Installation and Finished Product

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Looking at the back of the motherboard, there isn't a back plate used with the NH-L9i, just the addition of the four screws. The nylon washers will isolate these screws and keep things from shorting out.

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Once the NH-L9i is securely mounted, I stepped back to see that this cooler is in no way going to encroach on any of your memory choices, nor will it block any of the slots. The same can be said for this cooler not encroaching on the PCI-e slots either, so even with a Mini-ITX system, there is no need to worry about that happening.

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Since I am testing in an open air system with the board lying flat, the heat pipe orientation shouldn't matter. On that note, I didn't see where it said it shouldn't be installed any certain way, but I would assume the pies going side to side would work best.

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This is what will really show why this cooler is so special. For those of you that have dealt with SFF chassis before, tower coolers and smaller coolers just won't fit. With the NH-L9i the cooler is shorter that the memory and only the fan is peeking over the top.

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I like that there is enough height under the cooler to tuck in the fan cable and get that wiring managed. I also like the fact that there are no issues with clearance of the CPU power delivery heat sinks already on the board. You can also set this cooler to deflect its exhaust to the hotter heat sink and offering it some airflow to help keep things cool.

The Test System and Thermal Results

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I would first like to thank HIS, GIGABYTE , InWin and AVADirect for supplying products for me to test with.

Testing for the CPU coolers is done with the use of RealTemp to ascertain temperatures, Intel Burn Test to deliver the load to the CPU and CPU-Z to verify the CPU speed and the voltage being used in Windows. All of the testing is done with an ambient temperature of 24.5-25°C and humidity is maintained to 35% sometimes less.

For the "stock" runs, it's more of a plug and play setup where the PWM of the motherboard is in control of the fans speeds for both the idle and load results. Speed Step is active and the processor idles at 1600 MHz and loads at 3500 MHz for the stock settings. I also set the memory to run at 1600 MHz for stock. As for the overclocked runs, I load the CPU at 4.5 GHz and idle results are obtained with 7.5V to the fans while the load run is set to deliver 12V to the fans. This allows me to gauge the lowest and highest fan ratings for my charts.

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When I booted the PC and allowed it to rest for a bit, I was pleased to see RealTemp showing that the NH-L9i is able to keep the CPU at 26 degrees in its idle state. That is something the PWM on most tower coolers don't accomplish.

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With the stock clocks running on the 2600K, I loaded up the CPU with a bit of IBT, and I found the NH-L9i is more than capable of keeping most CPUs cool. In tighter spaces it will need assistance from chassis fans, but even with the TDP limit, I could overclock this CPU on stock volts.

Now in my conversations with Noctua, they wanted me to be sure to follow the TDP guidelines and not abuse the cooler too much. Even so I went ahead and tried the overclocked profile I always use just to see what would happen. With the increase at stock the cooler only jumped two degrees. Once I let IBT lose, there was a thermal shutdown of the CPU, but the NH-L9i hung in there for close to 20 minutes before it just couldn't cope any longer. This is why I say there is some room to play around, but you need to tend to chassis airflow to make this happen.

Noise Level Results

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With the PWM controls turned off, and the L.N.A. in place, the NF-A9x14 PWM fan registered at 30 dB of noise with 12V set as being supplied to the connection, then it is reduced by the L.N.A. to 7.5V to achieve this result.

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Removing the resistor and keeping the BIOS set to still deliver maximum voltage to the connection, all I was getting was an ever so mild hum coming from the cooler and registering at 41 dB for this test.

This is why I said there really is no need for the L.N.A. to be used, but it was nice of them to include it as an option on low TDP CPUs, where silence is important.

Final Thoughts

Even with the TDP limitations of the NH-L9i, I am really pleased with the results it delivered. Comparing it head to head against the Phanteks, while it may have been cheaper, it doesn't test as well, doesn't have the ability to take on other fans, and frankly, doesn't look as good. There is a more solid feel, and as I like to describe it, a more professional grade feel to the Noctua solution. The thickness of the aluminum used in the fins is always thicker than most others, and almost nobody solders on heat pipes these days. Noctua seems to bend all the average manufacturers rules as they offer products that take the competition head on and seem to almost always prevail. With the NH-L9i things haven't changed, this is a really impressive solution.

What impresses me even more is the shear amount of air flow and static pressure Noctua was able to pull out of this 14mm thick 92mm fan. I know most of you looked at that fan and thought that it really can't do much, it's just too tiny - well, Noctua definitely went to work with this new addition to their fan lineup. There really isn't a surface that is left untouched. The leading edge of the frame is made to allow a smoother inlet of air to the blades, and the insides of the frame have divots like a golf ball to disturb the air and keep it from staling near the frame. The shape of the blades is one thing, but there are grooves cut into each of them, and even the textured finish to the individual blades has its benefits. If you aren't really strapped down for room above this cooler, you always have the option to add a 25mm thick fan with the supplied hardware, and grab back a few more degrees as well.

Noctua may not have made a cooler that everyone is going to rush out and have to buy one to put in their PCs as soon as possible, but that really wasn't the idea in the first place. Taking the idea of bringing what I already love about Noctua, the silence, better quality, and being simple to use and install, and shrinking all of that love into this tiny little package, it's just amazing to me. Noctua didn't see any reason to lower their standards just because things need to be small and low-profile to fit in the SSF chassis side of PC builds; those customers deserve the best just the same as the people who can use a D-14.

With the small price of $46.99 to have to spend to acquire the NH-L9i, for those with compact space requirements, there are none better.

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Chad joined the TweakTown team in 2009 and has since reviewed 100s of new techy items. After a year of gaming, Chad caught the OC bug. With overclocking comes the need for better cooling, and Chad has had many air and water setups. With a few years of abusing computer parts, he decided to take his chances and try to get a review job. As an avid overclocker, Chad is always looking for the next leg up in RAM and coolers.

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