Cooler Master Nepton 280L Review

red454 - 2013-10-22 18:19:57 in CPU Cooling
Category: CPU Cooling
Reviewed by: red454   
Reviewed on: November 18, 2013
Price: $119.99

Cooler Master Nepton 280L Introduction:

A few years ago, water cooling was limited to those who were ambitious enough to attempt it - overclockers, hardcore enthusiasts, or just someone who wanted their build to stand out. And it certainly wasn't cheap. Remember the first time you saw a water cooling system on a computer? Amazing. I remember when I first saw one, and I remember thinking that one day I would have one whether I needed one or not!

Manufacturers caught on to the trend and developed the AIO or All-In-One systems. This took the guess work out of water cooling and allowed the average builder to enjoy the benefits (and bragging rights) of water cooling. They made it mainstream. Now some of the hardcore builders may thumb their noses at the AIO systems and argue that these systems are too broad, too vanilla, and that a true water cooled system must be custom built to be effective. But really, these AIO systems are not some cheesy after thoughts. There is a lot of engineering and testing that goes into developing an AIO. Now they are affordable and come in a variety of sizes. And case builders are regularly incorporating water cooling into their designs. This trend is not going away anytime soon.

Cooler Master's family of cases, power supplies and fans have been at the top of the short list for anyone looking for stylish, long-lasting, affordable hardware. Cooler Master jumped into the water cooling ring with the release of the Seidon and followed it up with the Eisberg series. While the Seidon was designed in-house, the Eisberg was developed alongside Alphacool, a German company. With a new pump designed exclusively for Cooler Master, the Nepton is its latest entry into the AIO (All-in-One) world of watercooling solutions. The Nepton is the first tool-free AIO watercooler and comes in two flavors, the 140XL and the 280L, and the 280L is the model we will review today. The Nepton uses thicker (13.7mm), longer tubing, JetFlo 140mm PWM fans, a new Ultrafine Microchannel water block, and this system can handle over 300 watts of heat dissipation.

Cooler Master Nepton 280L Closer Look:

The graphic on the front panel of the box shows a close-up view of the pump, tubing, radiator, and fans. The Nepton text and Cooler Master logo have a shiny silver foil effect and really stand out. Clearly stated are three features - Maintentance Free, Ultrafine Micro Channel, and Durable FEP Tubing.  FEP (Fluorinated Ethylene Propylene) was invented by DuPont and is used in a wide varitey of industrial applications. The water block lens is illuminated with white LEDs. Moving along to the rear of the box, we have a list of the socket coverage. Also the features are listed in eight languages, along with a performance chart and a detailed dimensional layout. 












On the wine-colored side we have all the specifiactions listed and again the socket coverage. The opposite side shows just the water block along with the silver Cooler Master logo and Nepton text.




And the wine color follows around the long side and includes the silver Cooler Master logo and Nepton 280L and socket coverage text.


Inside the box we have the formed fiber tray. Everything is held in position and protected by the shaped compartments.



After removing the items from the box, we have a better view of the contents: the radiator and water block, the mounting hardware, the fans, and of course, the instructions. The mounting hardware consists of a small tube of thermal paste, the common base mount for both AMD and Intel, and a variety of screws. Now I will let the cat out of the bag a little - one thing that I see are thumb screws. It seems that Cooler Master may have streamlined the installation process and we'll see about that shortly. Continuing on there is the water block mount for AMD and Intel motherboards, and then a power cable / splitter for the fans. This splitter allows you to power both fans from one motherboard fan header.



On to the next page to get a closer look at the details.

Cooler Master Nepton 280L Closer Look:

Looking at the system we see the typical AIO setup: a water block / pump with power lead, the ribbed tubing, and, finally, the radiator. The radiator feels solid and is of course filled at the factory. The first thing I notice is the oversized tubes. Thick, yet very flexible. And long, which should ease up on the usual twisting and pulling that you go through when getting the radiator into positon in the case. I also notice that there is only a single 4-pin power lead coming from the pump, so the fans are not controlled by the pump. And this is not necessarily a bad thing. In fact it helps to keep the cable clutter down.


















The radiator is the same size as a standard 240mm radiator and is constructed from aluminum. The inlet and outlet tubes are a hefty 13.7mm diameter and are secured to the radiator. The larger diameter tubes will allow a better fluid flow rate. There is a sealed fill port off to one side and it is clearly labeled with "Do not tamper with or remove" and "Warranty void if removed."



Here you can get an idea of the tube size. On both sides of the radiator there are tapped mounting holes for 120mm and 140mm cooling fans.



The pump cover has a thin hexagonal lens that surrounds the Cooler Master logo. When it is powered up, white LEDs make the hex shaped lens glow. Underneath you can see the two of the four mounting holes for the two brakcets that attach the water block / pump to the base. There are dedicated brackets for both AMD and Intel motherboards. Don't forget to remove the protective plastic cover that is stuck over the cold plate.



The inlet and outlets can be rotated slightly to allow for the tubing to conform to the way you mount the radiator. On the right you can see Cooler Master's new UltraFine Microchannel, which per Cooler Master is "designed for the best water flow and draws the maximum amount of heat away from the cold plate and transfers it to the coolant".



And here we have the included JetFlo 140mm fans. These are 4-pin PWM fans that use a rifle bearing and are rated at 0.8 amps and 54~122.5 CFM ± 10%. The speed is variable from 800~2000 RPM (PWM) ± 10%. 



The JetFlo 140's have integrated rubber pads at each corner to keep any vibrations to a minimum.



The base mounting bracket has a green insulating layer and studs with adjustable plastic clips. You insert the studs through the appropriate holes in the base and then pop the clips on and slide them to lock the studs to the proper location depending on your socket type. The clips do a good job of holding the studs in place as you install the bracket to the rear of the motherboard. Flip the bracket over and you are ready for an AMD motherboard.



So now we go to the installation. It is an understatement to say that there is plenty of room in the Phanteks Enthoo Primo case. The long tubes give you some welcome flexibility when installing the radiator. Here is where the thumbscrews really shine and reveal the beauty and utility of Cooler Master's tool-free AIO watercooler. It can be a little bit of a challenge when trying to hold the radiator in position and get a fan in there, and then get a screw started. How many times do you drop a screw, then everything shifts out of place? Not with the thumbscrews. This is a really great idea. Need to clean the fan or radiator? No problem - in a few seconds you remove them without any tools, and have them back in action in a snap.

The pump is powered by the CPU fan header on your motherboard. There are no fan controls (power leads) on the water block / pump. The power cable for the fans is actually a separate 4-pin splitter that plugs into the CPU optional fan header on your motherboard and allows you to power both of the 140mm fans. 




The sheer size of the Enthoo Primo case makes the 280L seem a little less dramatic, but it still takes up some space.


And now you can see the Intel mounting brackets. You use two screws to install one bracket on each side. Then you slide a plastic spacer over each stud on the base, place the water block over the four studs (on top of the spacers), and use the four thumbscrews to finally secure the water block to the base. The thumbscrews really simplify the pump installation.



Here is a better view of the two mounting brackets installed on the sides of the water block. I like to do a test install and check to see coverage and spread of the thermal paste, then I wipe it down and on to the final install.


And here we have the final build. It looks nice in there. The 140mm fans are ready to move some air.

Cooler Master Nepton 280L Closer Look:

Along with the standard 140mm JetFlo fans, I have the opportunity to take a look at the JetFlo 120mm fans. Not so much as a full-blown review of the fans, but to show how they work with the Nepton 280L. So let's get started.


The JetFlo 120 fans come in a nice box with a front flap that is held shut with a piece of Velcro. These fans come with LEDs in either red, blue, white, or none. Today we have blue. Open the front flap and you are met with a variety of information from the bearing composition to performace charts. The bearing is made from POM, which is known as Polyoxymethelene and is an excellent bearing material.





















The front of the box shows the fan with blue LEDs in action. The rear of the box shows the fan specification details and feature list in eight languages. Briefly some of the key specifications are: Fan Speed 800-2000 RPM ± 10%, 1600/1200 RPM (fixed) with the silent adapter. Air flow: 95 CFM ± 10%. Current: 0.4A.




The JetFlo fan boxes have the same color and text scheme as the Nepton box.



The fan is nicely packaged in a separate box with a small upper compartment for the extras. The bottom wall of the compartment has a little notch for the fan cable to pass through so it can be stashed away. Open the top and you are ready to remove the fan.



Out of the box we have the fan, two adapters for silent operation, and a small bag of four mounting screws. And yes that is a 4-pin connector!



Let's take a look at the fan frame. The plastic frame is thin and light weight - but not flimsy or cheap. The fan motor and blades are supported by four arms that are beveled for smooth air flow. One thing that stands out is that the mounts at each corner are rubber, and are secured with two socket head screws. There is a threaded metal insert in each rubber mount, and this insert is large enough for standard mounting screws to pass through.



If you want to keep things quiet, you have two included options in the form of adapters. Each will give you a lower level of speed and keep the sound down. The label says "Caution: Hot". Speed is typically reduced by using a resistor, and the resistor lowers the voltage at the expense of heat generation. In full PWM mode, you have a speed range of 800 to 2000 RPM +/- 10%, but both of the adapters will run the fan at a fixed speed, either 1200 or 1600 RPM depending on which adapter you use.


Now let's show how well the Nepton 280L works with 140mm and 120mm fans. For reference on the left are the stock JetFlo 140mm fans that come with the 280L. On the right are the JetFlo 120 fans installed.



Again for reference, I mounted one the of 140mm fans and one of the JetFlo 120 fans on top of the 280L.  I mounted both of the JefFlo 120 fans on top in a pull configuration and then I dimmed the lights - you can really see the blue glow of the JetFlo 120 fans.



And here I mounted the JetFlow 120 fans as pushers. They really light up the inside of the case. And you can see the white LED of the Nepton 280L pump. The JetFlo 120mm fans are right at home with the Nepton 280L. Performance wise, the JetFlo 120 fans kept up with the JetFlo 140mm fans, although they were perhaps a bit louder at full speed.

Cooler Master Nepton 280L Closer Look: 

The Cooler Master COSMOS SE will now make a special guest appearance to showcase the Nepton 280L on top and up front. This is convenient of course, since I recently reviewed the COSMOS SE, so why not put the Nepton and the COSMOS together and see what happens?

I will install the Nepton 280L at the top and in the front. First, we will see how well the Nepton 280L fits up top. There are mounting holes on top for 120mm and 140mm fans, plus some openings for fan cable passage. The top mount on the COSMOS is set up for the radiator to be mounted inside the case and the fans on top. I have the top cover removed to mount the fans. The thumbscrews make short work of the installation. First we install the 140mm fans that come with the Nepton. Next, I installed the 120mm JetFlo fans, and of course there is plenty of room.


















Inside there is plenty of room for the radiator. Depending on your motherboard, you may be able to get a second set of fans for a push / pull configuration, but my MSI Z87-GD65 motherboard has some interference with the VRM heatsinks. Mounting the radiator and fans on top is pretty straighforward. But mounting the radiator in front takes a bit more work. To properly use the radiator in front, you must remove all the hard drive cages and support frames. This is fairly easy and only takes a few minutes. The lower hard drive cage only needs to be moved, and we'll see that shortly. There are two special mounting brackets for a front mounted radiator in the COSMOS SE case, and I tried a test fit with just the radiator. No problems so far. Next, I will move the radiator back a little to make room for the fans, which I will install to the front of the radiator.



Here you can see how the upper hard drive cages are absent, but the lower cage is still there and it is separate from the upper cages. The COSMOS SE has mounts for two solid state hard drives that are integrated into the cage frame, so even if you remove the lower hard drive cage for more room, you can still install two SSDs. This would only be important if you choose to mount the radiator in front with four fans in a push / pull configuration. But the way I have it set up, I only need to move the lower hard drive cage and there are mounting holes that allow for two additional mouting positions.



I have the two 140mm fans installed. Again, the thumbscrews make this very easy. The special mounting bracket has holes for both 120mm and 140mm fans. After the fans are installed, I can pop the front fascia back on.



So let's see how the JetFlo fans look up front. As I suspected, plenty of room and they look great! Clearly the COSMOS SE and the Nepton 280L are right at home with each other.


Cooler Master Nepton 280L Specifications:

Radiator dimensions
311 x 139 x 30 mm ( 12.2 x 5.5 x 1.2 inch )
Fan dimensions:
140mm x 140mm x 25mm
Fan speeds (+/- 10%):
800~2000 RPM (PWM) ± 10%
Fan airflow:
54~122.5 CFM ± 10%
Fan dBA:
21~39 dBA
Fan static pressure:
0.7~3.5 mm H2O ± 10%
Fan Life Expectancy
40,000 hours
Cold Plate Material
Fan Specification
140mm (x2) 4 pin
Socket Support
Intel LGA 2011 / 1366 / 1150 /1155 / 1156 / 775
AMD Socket FM2 / FM1 / AM3+ / AM3 / AM2
Radiator Material
Low-permeability for near-zero evaporation
Pump Life Expectancy
70,000 hrs


Cooler Master Nepton 280L Features:


All information courtesy of Cooler Master @

Cooler Master Nepton 280L Testing:

Testing involved recording temperatures for the CPU during idle and load phases. The load was simulated by running Prime95’s small FFTs for one hour. The maximum temperatures were recorded using HW Monitor 1.21.0. Please note that the case is tested from its factory setup, including location of fans, unless otherwise noted.

Testing Setup:

Comparison Heat sinks:







The Nepton 280L is up against four CPU coolers that are air cooled. Idle temps were all close as expected, except for the BigTyp Revo, which ran a few degress higher than the others. But the Revo pulls air down on the radiator and pushes it over the motherboard. The higher temps for the Revo are likely more of an airflow issue. And for the most part, the air cooled units held up rather well. Under normal usage, the 280L is quiet. Load it up and you know it is there. Not overbearingly loud, but you do know that the fans are moving some air. Of course most new motherboards now have the ability to control your fans with custom profiles, so you can tailor your fan operation to your liking.

The cooling ability of the 280L is certainly adequate. It gets the job done. It does not run away from the air coolers or put them to shame, but one advantage with water cooling to keep in mind is the relatively small water block and significantly lower stresses it imparts on the motherboard. I also factor in the ability to access things like RAM and various fan headers and CPU power plugs that large air coolers usually all but cover up.

Overclocking on the 4770K was done at 1.248 volts, which held a solid 4.2 GHz.

Cooler Master Nepton 280L Conclusion

All-In-Ones are much more common than just a few years ago and many manufacturers offer them. And as they become more popular and affordable, manufacturers must come up with ways to sway the customer. So what makes the 280L stand out from the others? The Nepton is the first tool-free AIO watercooler and it is certainly capable of cooling your system.

But there is more to it than just cooling. For me it is the installation and the ability to move the radiator to the necessary position. And of course, how well it fits in your case. With some AIOs, it can feel like you are going to kink the tubes before you can get the radiator into position, especially in a smaller case. The longer, heavier tubes on the 280L help to alleviate that. And those thumb screws - wow, they really make the installation process so much easier. You can easily get the radiator and fans in position. And the thumbscrews make installing the pump a breeze - in fact, the thumbscrews alone would be a selling point for me. It wouldn't surprise me if that becomes a standard for other manufacturers.

The pump is quiet, and the fans are not terribly loud. I like the JetFlo 140 fans and the fact that they are 4-pin PWM fans. And while we are talking about fans, the JetFlo 120 fans are right at home with the Nepton, and prove that they can move the air when it counts. The rubber pads on the fans help keep any vibrations to a minimum. The splitter power cable for the fans also makes it nice to control both fans from one fan header, and it provides for a clean cable routing since you can run the fan cables and the splitter behind the motherboard tray and keep them out of sight.

And while the Nepton is well-suited for any case that can handle a 280mm radiator, I was particularly pleased with how well the Nepton 280L and the COSMOS SE case work together. It is as though they were made for each other. Well, I suppose there is probalby some truth to that. 

The Nepton is really a great addition to the Cooler Master family of CPU coolers. The installation went well, the performance was fine, and really the only con I can think of is that perhaps it would be nice to have a longer warranty - at least three years.