Cooler Master did a masterful job with the performance design of the Nepton 240M cooler, managing to coax decent performance out of the unit without the noise footprint you would normally expect. The unit's abilities did start to wane under the Haswell-E's heat onslaught, but it still managed to hold it own with performance scaling within expectations.


As of February 13, the Cooler Master Nepton 240M liquid CPU cooler was available at for $129.99 with Prime shipping, as well as B&H for $109 and for $129.99.


Cooler Master's Nepton 240M AIO cooler is a well designed unit, featuring top shelf performance without the noisy fans. The Nepton's design innovations begin with its ribbed FEP tubing, designed for maximum flexibility without the kinking associated with traditional smooth walled tubes. The unit's CPU block is copper based with a skived micro-channel base, maximizing the available surface area for heat exchange to the liquid medium. Block flow restriction caused by the micro-channel design is minimized by using an impingement plate over the inlet barb, forcing the water through the block at a high pressure than possible with the plate. The pump directly feeds the flow into the CPU block, further ensure maximum flow rate through the critical heat producing area. The Selencio fans included with the cooler were another stroke of genius on Cooler Master's part. The thicker blades of the fan are able to create better air pressure for airflow through the radiator while not creating the noise associated with thinner bladed fans. The higher air pressure works to the radiator's advantage with its higher density fin count.

The one questionable decision with this high performance cooler was the use of an aluminum-based radiator instead of a copper-based unit. Aluminum is good at tranferring heat between mediums (such as from the radiator fins to the air flowing though the radiator), but is not as good as copper at absorbing heat and transmitting it. A full copper radiator or a hybrid copper / aluminum radiator optimizes heat transfer. The other downside of using an aluminum radiator in tandem with a copper block come from galvanic corrosion. This effect causes the metal surfaces to corrode with the liquid medium acting as an electrolytic transfer medium. To combat this effect, corrosion inhibitors much be added to the liquid medium, reducing the heat transfer effectiveness of the coolant.


  • Performance under stock and overclocking conditions
  • Build quality of the cooler
  • CPU block and radiator barb rotational freedom
  • Tubing size and construction – ridged FEP prevents kinking
  • Low noise, high performance Selencio fans included with kit
  • Radiator fin count


  • Price
  • Use of aluminum radiator
  • Need for use of performance inhibiting corrosion inhibit because of mixed metals in loop
  • Possible galvanic corrosion over time as coolant chemicals breakdown
  • Machining marks on CPU block mounting surface

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