Cooler Master Nepton 280L AIO Liquid CPU Cooler Review

Cooler Master takes the basic idea of an AIO, beefs up all the components in the mix, and introduces the Nepton 280L to us for testing and review.

Manufacturer: Cooler Master
16 minutes & 1 second read time


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What we have seen over the years from Cooler Master, is a company that went from pushing a lot of the same products in as many variations as they could possibly make to a company that is now thinking outside the box and relying much less on previous ideas to carry them along. Don't get me completely wrong here, we did just look at the Cosmos SE, but while using the naming, even here they made a whole new design on the inside, updating it with all the latest and greatest features. When compared to the original design, the newer version plain blows it out of the water.

What brings us together today is that same basic strategy to improve on designs already in the wild, just that this time, we are dealing with CPU cooling. Everyone knows the basic idea of what the various All-In-One liquid coolers are all about, and what every company is currently offering. While Cooler Master did start with the Seidon series of coolers that fit this standard mold to the letter, they are now branching out with the design to offer customers more than what the standard AIO can bring to the table. There are also the Eisburg series of coolers that sort of prove my point. This is where Cooler Master took the basic AIO and added a new head unit to allow for a bigger pump as well as a bit more coolant to be added to the loop. In every series, it is easy to see that Cooler Master was not happy with the OEM AIO designs, and knew they could do better.

This is where the Nepton series of AIO coolers steps in. Here, Cooler Master is offering 140mm and 280mm versions of radiators, but even here they snuck in a little surprise. While these kits are shipped with 140mm fans in both the 280mm and the 140mm version, these radiators will also take on 120mm fans. Between the radiator and the pump, the super small diameter tubing is gone and replaced with larger diameter tubing, and the head unit is also an entirely new design. Even at first glance, it is easy to tell that this isn't the standard AIO solution, and that you be getting much better efficiency with this design: it is just that obvious.

Stick with us as we put the new Nepton 280L from Cooler Master through the same paces as every other cooler to hit the labs. With all the new components, increased diameter tubing, and a larger radiator we expect good things from this liquid CPU cooler. By the time we are done here today, I think, strike that -I know, that the Nepton 280L will be on your must-have list once you absorb the results this product delivers in our testing.

Specifications, Availability and Pricing

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The chart above addresses the Nepton 280L as the RL-N28L-20PK-1, and shows it will fit on all of the sockets that chips still sell for, and a couple that have long since been noted as EOL. The newly designed head unit, with a new cold plate design to raise the efficiency of the amount of heat the coolant can remove, is only three inches wide with the pair of fittings included. It is slightly less deep without them at 2.7 inches, and from cold plate to the top of the head unit, it stands only 1.9 inches tall. This head unit offers some nice features as well. Not only does it only consume 2.9W at 12V, but it is near silent at 25 dBA, can last up to 70,000 hours, has an LED ring on the top that is lit when powered, and runs at an amazing 7200 RPM. Connected to the swivel fittings on the right side of the head unit, Cooler Master uses three-eighths inch ID, FEP tubing, which increases flow and removes the water permeability factor.

The tubing is also covered in corrugated plastic to protect it from damage, as well as offer anti-kink functionality. At the end of these tubes, they are connected to an aluminum 280mm radiator that is in actuality 300mm long, 140mm wide, and is 30mm thin. The bonus feature here is that increased surface area leads to even more efficiency, and on top of that, there are 140mm and 120mm fan mounting holes in both sides of the radiator so customers have more choices of cooling levels with the fans they select to replace the stock ones.

Speaking of the fans, it is highly doubtful that you will want to replace the pair of 140mm JetFlo fans that are based on a new fourth generation POM bearing. These fans take power via a 4-pin PWM connector, and once fully powered, they are more than capable of taming the thermal testing. These fans are capable of speeds of 2000 RPMs, and at this speed they can deliver 122.5 CFM of air flow and 3.5 mmH2O of static pressure. Looking at the sound rating of 39 dBA: I have a feeling that these fans, while producing some big stats, are also going to be delivering a lot of noise when allowed to run at full speed.

Cooler Master also includes a second set of JetFlo fans, but these are the blue LED lit 120mm versions. These are also based on the new POM bearing, but the specs are somewhat lower. While these also spin at a similar RPM, rated near 2000, they deliver 95 CFM of airflow, 2.62 mmH2O of static pressure, and are rated at 36 dBA in the noise department. We will be testing both sets of fans, by themselves, on the Nepton 280L and will have these results in the charts.

This design is almost to the level of what we saw with the H220, but still being sealed and offering users that warm and fussy feeling they get from using an AIO over something more custom or customizable. Also, most of the dual radiator AIOs on the market release with a $119.99 price point, and all others are just the usual suspect as far as components and designs go. This fact makes the pricing of this much improved design seem that much better.

The previous pricing is for 240mm solutions and not 280mm solutions, and from what we were told, the MSRP of these new Nepton 280L coolers is only $119.99 US dollars. By the time we are done with this review, it will be very easy to see that not only is this a better solution than others are currently offering, but more like stealing it at this sort of a price point.


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Cooler Master offers a large image of the Nepton 280L, which is inside the box, at the top. Under that is the product naming, three icons denoting that it is maintenance free, has new ultra fine Micro-channels offering twice the surface area, and that it uses the Fluorinated Ethylene Propylene (FEP) tubing to eliminate coolant loss evaporating through the tubing. To the right is a silver box that denotes that this kit includes a 280mm radiator, two JetFlo 140mm fans, and the extreme level of performance it offers.

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Turning he box to the left to expose the right side, Cooler Master uses this to offer a close-up image of the head unit without power. Under that image there is the naming of the kit again, but it is followed by a listing of the eleven various sockets the Nepton 280L is compatible with, with the provided hardware.

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That brings us to the back panel where the Cooler Master logo, product naming, and socket information are again given. Below that, in eight different languages, there is a list of features. These include the pure copper water block, its Micro-channel technology, its sealed and maintenance free aspect, and ends covering the durability and power of the new pump. Across the bottom there are some test results that they have obtained in their testing, along with dimensional renderings of the head unit and the radiator.

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As we have come to expect with Cooler Master packages, there is always the purple panel. For the Nepton 280L, they have used this to display the specifications chart. This way, potential buyers have all the information they would need to make an educated decision as to if this would fit into their current chassis.

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The Nepton 280L is packaged like most other AIOs out there, and since it works so well, there is no need to change it. The recycled cardboard is pressed into a shape that spaces the contents from the outer packaging and separates the individual components. There is also a dense layer of foam that comes over the top of this to protect the product on all sides. As with all the rest, this packaging has delivered this AIO in very good shape and free from damages caused in transit.

Cooler Master Nepton 280L Liquid CPU Cooler

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Starting off with the new head unit, Cooler Master has placed their name inside the logo ring. Along with the textured plastic look of the pump cover, that logo ring will illuminate with white LEDs when it gets powered up.

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The head unit is a bit taller than most other AIO coolers, but I also notice different swivel fittings. These are actually part of the head unit, and not something screwed into the sides like most others. Just like all the others, you still have full flexibility to turn them to fit the installation.

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On the opposite side of the head unit, there is a braided cable that comes from the very bottom by the base. This ends in a 4-pin PWM connection to connect the pump for power and speed control.

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Cooler Master uses a plastic sticker to protect the mating surface during transit; it is noted to be pulled off prior to installation. I do like that there is no pre-applied paste full of debris like we have seen before.

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The base has milling marks left in its finish of the pure copper base plate. Also notice that the screw heads have changed to TA or triangle shaped to lessen the chance users will try to open it. On the back side of this plate is a very finely finned section with a wide groove running down the middle. This adds twice the surface area as a normal AIO plate, and the channel improves the flow as well.

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Between the head unit and the radiator, Cooler Master provides the Nepton 280L with more than fourteen inches of FEP tubing that has been stretched to fit over the barbs and fittings. Between the two ends, that FEP tubing is protected with the plastic covering, and it lessens the chance of kinking the tubing inside of the case.

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This end of the tubing ends as it is stretched to fit over the aluminum barbs. Off to the right side there is a cap on another port. This is how the units are filled, and the sticker plainly says not to remove it, as it will void the two year warranty.

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The Nepton 280L, just by its naming, suggests it uses an all aluminum 280mm radiator, and it does. The bonus with this design is where you can mount the stock 140mm JetFlo fans; there is also a wider spacing setup to allow 120mm fans to be used instead, or as with the stock fans in push/pull.

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Upon closer examination of the radiator, there are quite a few of the fins askew from their intended orientation. We did take the time to straighten these out slightly, and these damages seem to have happened before transit, as the plastic liner showed no signs of scratching against these.

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Jumping ahead a bit, we grabbed the pair of 140mm JetFlo fans and strapped them onto the radiator to show how well they look, and how much of the fins are covered. These fans come with rubber pads on all four corners, on both sides, and as the specs alluded to, should be more than capable of good results.

Accessories and Documentation

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This is only half of the hardware provided with the Nepton 280L. Here we are given a Y-splitter cable to control both fans from one header. In the middle there are the AMD head unit brackets, the universal back plate, and the Intel brackets. There is also a tube of grey Cooler Master thermal paste worth three or four applications.

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This set of hardware contains the clips to lock the back plate studs, the mounting nuts for the head unit, screws for the socket brackets, and LGA2011 screws down the left. The middle has two sets of long screws. One set is slightly longer to allow the thickness of the chassis, while the other set are slightly shorter to mount fans on the opposite side. To the right there are black spacers, shorter radiator mounting screws, and at the bottom are the studs that lock into the back plate.

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The 140mm JetFlo fans use seven blades with quite a bit of spacing between them to deliver all the force they are rated for. If you are looking to double the amount of fans on your Nepton 280L, look for the A14025-20RB-4CP-F1 version for the ultimate efficiency this kit could potentially offer.

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There is also some paperwork to not only help you through the installation process, but there is also the warranty information insert, which shows the terms and conditions of the two year manufacturer's warranty.

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The instruction show what screws should be used where, and this also helps explain what I meant about the longer set of fan screws being used to mount the radiator to the chassis. Even though these are just renderings with letters and arrows to follow, text is really not needed, the kit is very user friendly, and if you ever used an AIO before, this one will be a pleasure to put together and get mounted.

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After choosing and mounting the correct brackets to the head unit, and have the back plate set up, you simply mount the head unit onto the socket. Then of course you need to plug in both the fans, as well as the head unit, and you are ready to use the Nepton 280L.

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As I mentioned previously, we were also given a set of JetFlo 120mm fans. These are smaller in diameter, but are still powerful solutions for the task of cooling the 280mm radiator. These are Performance fans that come with noise adapters, but pack up to 95 CFM. These are also based on the new POM bearing and the charts show what sort of pressure curve and acoustics to expect from them.

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If not for the clear fins, these are just smaller and slightly less powerful version of the JetFlo 140mm fans. They have the same rubber pads, and the same brass screw sleeves. What sets these apart is that they come with noise adapters as well as being blue LED lit when powered.

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The JetFlo 120mm fans cover much less area than the 140mm version did. Something you really need to consider is the 120mm fan spacing. Not many cases will have this offset by default for 120mm fans. However, you could always put the 140's at the top and add a pair of these like we have so the offset is irrelevant.

Installation and Finished Product

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Here we have taken the studs and pushed them through the back plate. Be sure when adding the holder clips on the tabs that they are pushed in to the second position. The sides clip into grooves and naturally push the studs inward rather than easily accepting them into the locked position.

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With the studs and the clips all sorted out, the back plate easily fits into the mounting holes of the motherboard. That greenish bit acts as the isolation material to keep the plate from shorting against the motherboard.

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Flipping the board over allows for the placement of the black plastic risers. Place one on each stud, as this is the final height for the block hardware to be tightened to for the best mounting pressure.

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Grabbing the Intel brackets, all we had to do was orient the tabs to bend toward the base plate, rest it on top of the spot to mount it, and to secure it, the screws run up from the bottom and screw into threads in the holes of the metal brackets above.

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Make sure to remove the plastic base cover, add some thermal paste, and then set the head unit onto the hardware. At this point, all that is left to do is to screw down the nuts in an X-pattern until they stop spinning to maximize the mounting pressure.

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Even though the Nepton 280L comes with a taller head unit than most, behind the Trident X memory, there is nothing of it to be seen, and it causes no conflicts with any of the slots.

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The fitting of the head unit is next to the memory, but you can see there is plenty of clearance between it and the memory dust cover installed in the unused slot. We have also plugged in the 4-pin from the pump into the CPU header, and we used the splitter cable to connect the pair of JetFlo fans, which also adds a bit of length to help manage the cabling a bit cleaner.

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Since we had the 120mm fans on the radiator last, with the use of a few zip strips we mounted the radiator to the back of the chassis. Since there is rubber pads on the fans there are no worries of damaging the paint either.

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Once the system is powered up, the Nepton 280L comes to life. This is when the ring around the Cooler master name on the head unit starts to glow white, and while the JetFlo 140mm fans have no LEDs, the 120mm ones glow with a brilliant blue color.

The Test System and Thermal Results

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I would first like to thank ASUS, InWin, Corsair and Fractal Design for supplying products for me to test with. To see our testing methodology and to find out what goes into making our charts, please refer to our CPU Cooler Testing and Methodology article for that information.

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At stock levels of the 4770K, the Nepton 280L pushes the others aside as it takes top honors with both the 120mm and the 140mm JetFlo fans. As the unit is shipped, when tested, the Nepton 280L registered an average of 47.75 degrees across the cores. When the JetFlo 120's were installed the temperature increased slightly to 49.5 degrees. We did run a push/pull configuration with the 120mm fans pushing and the 140s pulling; there we saw a 46 degree result.

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This is where the efficiency and performance is really put up against the wall, and where weaker solutions will show their true colors. With the new components, thicker tubing, and the fans the Nepton 280L shows up the rest of the coolers on the chart. With the 120's on the radiator the result is 69 degrees, but with the 140's on it, the temperature dropped to 67.83 degrees averaged across the cores. It gets better. In that same push/pull configuration the result was an amazing 65.25 degrees for the average.

Noise Level Results

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Remember when we looked over the specs, there was an inclination that the fans may be a bit loud; well here is what we heard during the stock runs. The 140mm fans are more silent at 33 dB as they spun at 1262 RPM at this setting. The JetFlo 120s are a touch louder with the RPMs running at 1584, delivering 35 dB of noise level.

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With twelve volts now surging through the fans, the sound levels jump way up to very audible, almost to a too loud for comfort levels. The JetFlo 120s will spin at almost 2300 RPM while delivering an easily audible 71 dB of noise, even more than the Tundra coolers. Coming in at just less than the stock cooler, the 63 dB of noise produced from the JetFlo 140s at 2000 RPM, shows that neither solution is silent when you want the most out of the Nepton 280L.

Final Thoughts

If you want the best in AIO coolers; look no further than the Nepton 280L. Cooler Master proves that with a little customization, some serious developments in a new head unit, and some "take no prisoners" style fans, they have delivered the best AIO to date or any CPU cooler on these new charts for that matter. The kit is all inclusive with everything you will need. The hardware is very secure, rigid, and easy to work with. Mounting both the head unit to the motherboard as well as getting the radiator into the case is also made easier due to the fact that all the screws used knurled ends, so you can do everything with fingers to get them in place, and secure later with a screwdriver. The Nepton 280L took on the competition and made them all eat dust as it hit the NOS to boost into first place in our thermal results. The box says to expect extreme performance right on the front, and with results like these, they have definitely delivered exactly that.

That level of performance is definitely at the expense of your ears though. These fans are some of the highest rated in airflow and static pressure that we have tested with in quite some time. To get the cooling efficiency that we saw, speed of the fans has to be fast, and with that comes chopping the air coming into the fans. The nice thing about this is that you always have the option to allow the PWM controls on your motherboard keep the fans at a more enjoyable level, but at the expense of some of the performance. For normal gaming and workloads this is fine, but for those of you looking to gain every last drop of overclock from your chip, you are going to be dealing with quite the roar coming from that system with the Nepton 280L attached.

As for the pump, it was more silent than the fans in any aspect of testing. For all of our testing the pump was set to run at maximum potential. In this sample, that was 7250 RPMs. With the PWM curve in control, at the low-end speeds will vary, but our spun near 4000 RPM when idling. The transfer plate, and the thinner grooves and channeled design are definitely more efficient as well. We have seen other 280mm AIO solutions, and none are as efficient as this is. On top of the performance, the head unit is solid, has the cool lit ring on top of it, and offers the beefiest angled fittings I have seen on any AIO.

When you get down to it, and are ready to buy this AIO (and at this point I have a good feeling that a lot of buyers will be lined up to make a purchase), we have to consider the pricing. Considering that this kit retails at $119.99, and comes at the same price as most of the 240mm solutions out there currently, it is easy to justify this purchase. Especially when you consider that this is an all new head unit with all the bells and whistles, there is now an increase in the diameter of tubing to allow for better flow from this new pump, and the fact that they packaged fans that may feel like they want to levitate on their own, but will handle just about anything you can throw at it. I for one am a huge fan of the Nepton 280L design and performance, and bottom line: they are almost not charging enough for what they have just delivered.

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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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