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Cooler Master's Nepton 240M liquid cooler reviewed

Winter is coming
— 3:15 PM on October 21, 2014

I've always been fascinated by liquid-cooling setups for PCs. When I started building my own computers about a decade ago, liquid cooling had an exotic mystique. It was the mark of the most dedicated enthusiast, a mad-scientist-y whirl of custom water blocks, home-brewed tubing setups, and radiators pressed into Frankensteinian service from wherever they could be found.

Those mad scientists are still out there, but liquid cooling has become much more egalitarian of late. There's a dizzying array of closed-loop liquid coolers, or CLCs, available to the PC builder. CLCs do away with the complexity of fully custom loops in favor of plug-and-play designs.

That brings me to the cooler I'm looking at today, Cooler Master's $130 Nepton 240M. The Neptons represent the high end of Cooler Master's CLC lineup. These offerings include larger-diameter flexible tubing, higher-quality fans, and a more advanced water block design than the company's less expensive Seidon CLCs. With a 240-mm radiator, the Nepton 240M should have enough thermal capacity to handle even the hottest-running of today's processors. Let's take a look at the goodies Cooler Master has packaged with the Nepton 240M, and then we'll put it in the hot seat.

At first glance, it's easy to dismiss CLCs as a "seen one, seen 'em all" deal, but that would be a mistake. While the general principles remain the same from one to the next—an integrated pump and water block unit circulates coolant through a sealed radiator loop—there's still plenty of room for manufacturers to put their own spins on the concept.

Let's start with a look at the pump and water block on the Nepton. According to Cooler Master, the water block in the Nepton series features "ultra-fine micro channel" technology, which makes for an internal surface area that's four times larger than water blocks from "the competition." While I can't tear into the Nepton 240M to verify this claim, more surface area in the water block should make for better heat dissipation, so long as the ultra-fine fins don't impede coolant flow.

The copper mating surface on the water block isn't polished to a mirror sheen. Instead, it's ever-so-slightly grooved, perhaps to ensure that thermal paste can be squished into contact with as much of the plate as possible.

The pump inside the Nepton 240M isn't a run-of-the-mill unit, either. Cooler Master says it can move 120 liters of coolant per hour while producing only 11 dBA of noise. The company doesn't say how it arrived at this impressive noise figure, but the cheaper Seidon 120V has a vaguer "less than 23 dBA" noise rating, so the Nepton pump should be noticeably quieter than its sibling. (In my experience, the Seidon's pump is pretty coarse-sounding.) When the Nepton 240M is powered on, a white LED illuminates the Cooler Master logo on the pump, too. Fancy.

The business end of the Nepton 240M is its 240-mm radiator. This heat exchanger is joined to the pump by a pair of flexible, ribbed tubes. True to Cooler Master's specs, these tubes have a noticeably larger diameter than those used on the Seidon 120V. The radiator is about as thick as the Seidon's—just doubled in length. Out of the box, the radiator had zero bent fins, which I find reassuring from a quality-control standpoint.

There's a fill port on the radiator, but it's plastered with "warranty void if removed" stickers. (This is a sealed system, after all.) Should a problem arise with your Nepton 240M, Cooler Master backs up the Nepton line with a five-year warranty.

Left: the Silencio 120. Right: the Seidon 120V's stock fan.

On the active-cooling front, two of Cooler Master's new Silencio 120 fans ship with the Nepton 240M. In contrast to the seven-bladed fans packaged with the Seidon 120V, these 120-mm blowers each have five broad blades with much more aggressively swept tips. True to their name, the Silencios are rated to produce only 11 dBA of noise in operation. Cooler Master includes a rubber gasket that's designed to sit between the fans and the radiator, hopefully dampening unwanted vibrations from these air movers.

The final element CLC buyers will likely consider is CPU socket compatibility. Cooler Master includes mounting hardware to secure the Nepton 240M to virtually every Intel and AMD socket that one might find in use today, from LGA775 and Socket AM2 to LGA2011 and Socket FM2+.

Overall, the Nepton 240M appears to have all of the right stuff for a high-end CLC. It comes at a price, though. Cooler Master's MSRP for the Nepton 240M is $129.99, which is about $15 more expensive than the best 240mm CLCs from Corsair and other manufacturers.  Let's hope that its performance matches this lofty figure.

Next, I'm going to strap the Nepton 240M to a processor and see how logical and user-friendly the mounting system is.