Cooler Master Nepton 240M All-in-One Liquid Cooler Review

Cooler Comparison Testing

Cooler Testing Methods

To best gage the quality of the system coolers under review, system CPU temperature and cooling system audio measurements were taken with the CPU idle and under load. To replicate CPU idle conditions, the system was rebooted and allowed to sit idle for 10 minutes. To replicate a stress system load, Aida64 System Stability Test was used in conjunction with EVGA OC Scanner X for 30 minutes per run. After each run, the system was shut down and allowed to rest for 10 minutes to cool down. Then the CPU cooler was removed, cleaned, and remounted to the CPU with fresh thermal paste applied. This procedure was repeated a total of 12 times for each cooler – three times each for the stock and overclocking speed runs on the Z87 and X99-based systems.

Temperature measurements were taken directly from the CPU thermistors using RealTemp (the newer Tech|Inferno edition) for the Z87 testing and CoreTemp v1.0 RC7 for the X99 testing. Because of the volatile nature of the Haswell and Haswell-E thermistor readings, the system temperatures were measured as follows. For idle temperatures, the highest recorded value was used for the run. For load temperatures, a series of three values were notated: the average (high and low) across all cores, the average (high and low) across the single highest core, and the high temperature.

To adequately measure the Cooler Master Glacer 240L liquid cooler performance, performance testing was done for all scenarios under dual fan mode only. Quad fan mode operation was not run because no fans with performance equivalent to the Cooler Master provided fans were available. Fans were directly connected to the PSU and run at full speed for all tests performed.

Note that the temperature values are reported as deltas rather than absolute temperatures with the delta value reported calculated as CPU temperature – ambient temperature. For all tests, room ambient temperature was maintained between 23-27C. Sound measurements of the system cooler where taken with the sound meter placed 3 feet away from the system with all other devices in the room silenced. The Sound Meter Pro applet on a Samsung Galaxy S3 mobile phone was used to measure decibel level.

Intel Z87-based Haswell System Testing

CPU Stock Speed Testing

The CPU stock speed testing was conducted with the BIOS defaults set for the CPU (including enabling of the CPU-integrated graphics processor) and Turbo Mode disabled, equating to a 3.4GHz CPU speed, 1600MHz memory speed, 3.4GHz ring bus speed, and 100MHz base clock. The Intel Speedstep functionality remained enabled for the duration of the testing to get realistic CPU idle performance conditions.

The Nepton 240M AIO unit performs well compared with the other coolers with the Haswell at stock speeds.

CPU Overclocked Speed Testing

The CPU overclocked speed testing was conducted with known stable settings from a previous board review with Turbo Mode disabled, equating to a 4.68GHz CPU speed, 1780MHz memory speed, 4.0GHz ring bus speed, and 167MHz base clock. Also, the CPU-integrated graphics processor was disabled to reduce the processor heat generation. The Intel Speedstep functionality remained enabled for the duration of the testing to get realistic CPU idle performance conditions.

Board voltage settings were configured as follows:

• CPU Core Voltage – 1.25 + 0.005
• VCCIN Voltage – 1.90
• DRAM Voltage – 1.55
• CPU Ring Voltage – 1.125 + 0.005
• CPU SA Voltage Offset – +0.100
• CPU IO Analogue Voltage Offset – +0.100
• CPU IO Digital Voltage Offset – +0.100
• PCH 1.05 Voltage – 1.120

With the heat from an overclocked Haswell to contend with, the Nepton 240M still manages to hold its own against the other coolers with its performance scaling as expected. Surprisingly enough, there is no performance difference between the Nepton and the Glacer AIO units, even with the Glacer's copper radiator giving it a theoretical upper hand.

Intel X99-based Haswell-E System Testing

Note that for the X99 Haswell-E system tests, two sets of overclocking performance numbers are reported. This was done because of disparities seen while testing air coolers in conjunction with the X99-based system. The air coolers could not keep the system stable at the same overclocked speeds that liquid-based coolers were able to maintain.

CPU Stock Speed Testing

The CPU stock speed testing was conducted with the BIOS defaults set for the CPU and Turbo Mode disabled, equating to a 3.0GHz CPU speed, 2133MHz memory speed, 3.0GHz ring bus speed, and 100MHz base clock. The Intel Speedstep functionality remained enabled for the duration of the testing to get realistic CPU idle performance conditions.

With a Haswell-E processor at stock speeds, the Nepton 240M is able to maintain system temperatures equally those of the other coolers tested.

CPU Overclocked Speed Testing – Maximum air cooled speed

The CPU overclocked speed testing was conducted with known stable settings from a previous board review with Turbo Mode disabled, equating to a 4.25GHz CPU speed, 2666MHz memory speed, 3.5GHz ring bus speed, and 125MHz base clock. Also, the CPU-integrated graphics processor was disabled to reduce the processor heat generation. The Intel Speedstep functionality remained enabled for the duration of the testing to get realistic CPU idle performance conditions.

Board voltage settings were configured as follows:

• CPU Core Voltage – 1.275
• DRAM Voltage – 1.23
• All other settings set to Auto or stock settings

The performance of the Nepton 240M cooler starts to taper off once we upped the speed of the processor. THe Nepton cooler still outperforms the Noctua air cooler, but remains 3-5C behind the other liquid coolers tested.

CPU Overclocked Speed Testing – Maximum liquid cooled speed

The CPU overclocked speed testing was conducted with known stable settings from a previous board review with Turbo Mode disabled, equating to a 4.50GHz CPU speed, 2666MHz memory speed, 3.5GHz ring bus speed, and 125MHz base clock. Also, the CPU-integrated graphics processor was disabled to reduce the processor heat generation. The Intel Speedstep functionality remained enabled for the duration of the testing to get realistic CPU idle performance conditions.

Board voltage settings were configured as follows:

• CPU Core Voltage – 1.35
• DRAM Voltage – 1.23
• All other settings set to Auto or stock setting3s

The Nepton 240M's performance falls further as we apply even more speed to the processor, equating to more heat fo the unit to dissipate. With the 5960X running at its maximum stable speed, the Nepton 240M remains 5C behind its competitors.

Sound Testing

Cooler Master made a nice choice pairing the Nepton 240M with the 120mm Selencio fans. The fans have a higher than expected RPM rating, given their modest power consumption numbers. This minimizes the unit's noise footprint to the point that it remains barely audible above the system fans when running at full speed.