Cooler Master’s Nepton 240M closed-loop liquid cooler was a staple of our System Guides until it fell victim to a patent lawsuit a little over a year ago. The company didn’t let that setback end its quest to keep CPUs chilly, though. Its revised MasterLiquid Pro CPU coolers, introduced earlier this year, incorporate a distinctive two-chamber pump design that “sprays” coolant on the center of the fin array atop the CPU cold plate. The MasterLiquid radiators also use a rectangular fin design that purports to offer better heat transfer than the V-shaped fins on more traditional radiators.
Today, we’re looking at two CPU coolers that incorporate these design innovations: the MasterLiquid Pro 240 and the MasterLiquid Pro 280. Although these coolers use the same pump to move coolant through their closed loops, they offer distinctly different approaches to transferring heat once the coolant leaves the pump housing.
The MasterLiquid Pro 240 uses a one-inch-thick (2.5 cm), 240-mm radiator connected to its pump with Cooler Master’s trademark ribbed tubing. Our example isn’t entirely representative of the MasterLiquid Pro 240s buyers will get. Newer versions of this cooler will use smooth tubing with a webbed-nylon exterior.
To move air through the Pro 240’s rectangular-finned radiator, Cooler Master uses a pair of its latest 120-mm MasterFan Pro Air Balance spinners. We recently examined these fans in our review of the MasterAir Pro 4, but in brief, they’re sleeve-bearing units powered by the same type of “silent driver” Cooler Master says is under the blue-backlit window of the MasterLiquid Pro series’ pumps. In their radiator-ready form, they offer four noise-dampening rubber corners joined to the fan frame by four beefy Allen-head screws. I’m a real fan of the way these fans look—they’re subtle and classy.
The MasterLiquid 280 uses the same one-inch-thick radiator design as the MasterLiquid Pro 240, but it’s scaled up to accept a pair of 140-mm MasterFan Pro 140 Air Pressure spinners. These fans trade the “balanced” design of the Air Balance series for five broadly-swept fan blades. That design should help push more air through the tightly-packed fins of the Pro 280’s radiator.
Both MasterFan spinners offer three speed settings—”silent,” “quiet,” and “performance”—that can be selected using a switch on the back of the fan hub. The switch basically caps the PWM range of each fan.
For the MasterFan Pro 120 AB, the PWM range starts at 650 RPM and extends up to 1300 RPM in silent mode, 2000 RPM in quiet mode, and 2500 RPM in performance mode. The MasterFan Pro 140 AP fans start at the same 650 RPM base speed and spin up to 1550 RPM in silent mode, 2200 RPM in quiet mode, and 2800 RPM in performance mode. Cooler Master ships each fan in its silent mode by default, and that’s the setting we’ll be using in today’s testing. Builders who can tolerate more noise in trade for better airflow will be happy to have the option with these coolers, though.
While we can’t take apart the pump on these coolers to see what’s inside, the MasterLiquid Pro pump head does strike a distinctive profile, perhaps as a consequence of its dual-chamber design. Compared to the Nepton series before them, the MasterLiquids’ pump moves the inlet and outlet hose fittings to opposing sides of the housing, and it offers a fancy blue-LED-backlit window and ring around the base of the unit. Builders will need to be OK with that blue hue, however, as the MasterLiquid series is sitting out the RGB LED craze for now.
One thing Cooler Master didn’t change is the hefty hunk of copper that’s responsible for transferring heat from the CPU to the loop. Beyond the visceral joy that a big hunk of highly heat-conductive metal offers, the MasterLiquids both have an extremely finely-brushed finish on their bases that’s a far cry from the coarsely-brushed copper on the Nepton series. We expect most builders won’t be spending a lot of time admiring the base of their CPU heatsink, but Cooler Master’s work here gets full marks.
The mounting system for both of these heatsinks works with all AMD sockets from AM2 and FM1 on, plus all Intel sockets from LGA 775 on. The foundation for each unit works on the same principle of the MasterLiquid Maker 92: four bolts clip into a universal base and pass through the motherboard and mounting ears on the cooler, while four nuts screw onto those bolts and hold the whole assembly together. This system is quite simple and intuitive to install, but builders will want to use a flat-headed screwdriver to put the finishing twist on the four top nuts.
Once the entire cooler is safe and sound on the motherboard, it plays nicely with most everything around the notoriously tight Z170 socket—we can still use four DIMMs and install graphics cards on motherboards with PCIe x16 slots in the first position. Finding an appropriately-sized radiator mount in your case will be up to you, though.
To cut fan vibrations even further, Cooler Master provides a rubber insulator with both of these coolers that goes between the fans and the radiator. With this insulator in place, the full height of the MasterLiquid Pro stack is about 52 mm (or two inches), while leaving it in the box cuts that figure to about 50 mm.
In either configuration, the MasterLiquids shouldn’t run into motherboards in well-designed cases with top fan mounts, but be sure to check your case’s owner’s manual before buying either of these coolers to be sure.
Now that we’ve snugged down the MasterLiquid Pro 240 and Pro 280, let’s see how they handle the heat.
Our testing methods
Here are the specifications of our test system:
|Processor||Intel Core i7-6700K|
|Motherboard||ASRock Z170 Extreme7+|
|Memory||16GB G.Skill Trident Z DDR4-3000 (2x8GB)|
|Storage||Kingston HyperX 480GB SSD|
|Power supply||SeaSonic SS-660XP2|
|CPU cooler||Cooler Master MasterLiquid Pro 240
Cooler Master MasterLiquid Pro 280
Cooler Master MasterAir Pro 4
|OS||Windows 10 Pro|
Our thanks to ASRock and G.Skill for their contributions to our testing system, and to Cooler Master for providing the heatsinks we used in this review. We’ll be using Cooler Master’s own MasterAir Pro 4 heatsink as a point of comparison for these liquid coolers.
Our heatsink testing cycle comprises the following phases:
- 10 minutes idling at the Windows 10 desktop
- 20 minutes running the Prime95 Small FFTs CPU torture test
- 10 minutes idling at the Windows 10 desktop
We used the following software in our tests:
Here are the results of our cooling tests, plotted over time:
And here are the minimum and maximum temperatures reached during each testing phase:
With a stock-clocked Core i7-6700K underneath, both of these coolers are more than up to the task of keeping the CPU cool. The MasterLiquid Pro 280 only cuts a degree off the Pro 240’s maximum load temps, but both liquid coolers are doing a better job than the MasterAir Pro 4 and its single 120-mm fan. Let’s see how much noise the liquid coolers produce while they’re doing their thing.
Here are the noise levels we recorded for each cooler at idle and under load. We collected this data using the Faber Acoustical SoundMeter app running on an iPhone 6S Plus. Each measurement was taken 18″ from each cooler.
At idle, the only sound from either of these coolers will be the quiet (but still noticeable) noise from the pump heads on these coolers. Both MasterFan variants are practically inaudible at idle. That said, they’re still ever-so-slightly louder than the MasterAir Pro 4 and its pump-free tower.
With a stock-clocked load underneath, the MasterLiquid Pro duo sets itself apart from the MasterAir Pro 4. Compared to the air cooler’s 43.4 dBA result, the MasterLiquid Pro 240 shaves off an impressive 7.6 dBA, and the MasterLiquid Pro 280 is a whopping 8.9 dBA quieter. Going by the rule of thumb that a 10 dBA increase results in a perceived doubling of loudness, these coolers both deliver an impressive and immediately noticeable reduction in load noise compared to the MasterAir Pro 4.
Of course, absolute noise levels are just one characteristic of the perceived loudness of a cooler. Subjectively, the Pro 240’s 120-mm spinners sound excellent while cooling a stock-clocked CPU. They make next to no perceptible noise at idle, and their largely broad-spectrum noise character under load is only disturbed by a slight high-midrange tonal whir.
For builders who want an even quieter-sounding cooler, the MasterLiquid Pro 280 is the undeniable champion in our tests. Like its 240-mm counterpart, the Pro 280’s fans are practically inaudible at idle, but they maintain a soft and pleasant broad-spectrum character under load.
Despite Cooler Master’s re-engineered “silent driver” in the pumps of these coolers, the MasterLiquids both produce a soft but noticeable whir at idle. We tested both pumps at full speed, but unlike the Neptons before them, the MasterLiquids seem to have a bit of PWM range built into their pumps, so it might be possible to quiet them down even more under light load with the right fan curve. Even so, Cooler Master’s new pump isn’t obtrusive-sounding, and it’ll probably be next to inaudible in a case.
A quiet system is just one reason to choose a liquid cooler over a huge tower-style cooler—overclocking prowess is another. We turned up the clocks and voltage on our Core i7-6700K to see just how well the MasterLiquid Pros handle the extra heat.
Our particular i7-6700K runs well at 4.6 GHz and 1.312V, as reported by the ASRock Z170 Extreme7+ motherboard in our test rig. At those settings, the MasterLiquid Pro 240 held the chip to 90° C with an artificially punishing Prime95 Small FFTs load running at full tilt. At that temperature, the MasterLiquid Pro 240 produced 43 dBA, and its noise profile sounded about the same as the MasterAir Pro 4’s. That’s not surprising, given that both coolers use the same 120-mm fans. Since the MasterAir Pro 4 produced temperature and noise results that are near-identical to the Pro 240’s, this liquid cooler’s appeal for overclockers may be that it can fit into smaller cases where the Pro 4 tower can’t go.
Both the Pro 4 and Pro 240 probably have a bit more thermal headroom in them, since we tested each cooler with its “silent” performance profile. However, any increases in fan speed—and reductions in temperatures—will come with proportional increases in noise levels, and these coolers are already quite audible with an overclocked CPU underneath.
The MasterLiquid Pro 280 also held our overclocked i7-6700K to 90° C, but it did so while producing just 37 dBA in its silent mode. For a genuinely quiet overclocked system, the Pro 280 seems like an ideal pick. Recall that the Pro 280 only produced 34.5 dBA with a stock-clocked CPU underneath, so it’s not working much harder to keep the i7-6700K in check. What’s more, the higher-speed “quiet” or “performance” profiles for the MasterFan 140 AP spinners could offer enough airflow through the Pro 280 to keep even an overclocked Haswell-E or Broadwell-E CPU cool.
Cooler Master’s MasterLiquid Pro coolers improve on the company’s already-impressive Nepton series of heatsinks. They’re just as easy to mount as their predecessors, and even with their fans in their “silent” mode, these all-in-ones are more than up to the task of cooling Intel’s demanding Core i7-6700K CPU. If I had one complaint about these coolers, I wish the MasterFan 120 AB spinners on the MasterAir Pro 240 were slightly less tonal-sounding under load—but that’s really all I can come up with.
Compared to the performance of the $45 MasterAir Pro 4, the more expensive MasterLiquid Pro heatsinks kept our stock-clocked CPU cooler under load—and did so more quietly—in exchange for a slight (but barely noticeable) increase in noise levels at idle. The $130 MasterLiquid Pro 280 runs slightly quieter under a stock-clocked load than its 240-mm counterpart, so the only question builders will need to answer (assuming they have a 280-mm radiator mount in their cases) is whether that extra solace is worth $15 to $25 or so over the price tag of the smaller Pro 240.
Turn up the clocks on that Core i7-6700K, however, and some meaningful differences emerge between these two coolers. The cooling performance of these units is about the same with our test CPU overclocked to the hilt, but the MasterLiquid Pro 280 stays a whopping seven dBA quieter than the Pro 240 under that same load. For an overclocked PC that stays polite, the Pro 280 should be near the top of any builder’s list. The MasterLiquid Pro 240 isn’t actually any better for overclocking our test chip than the MasterAir Pro 4, but its remote radiator means it can go places the big tower cooler can’t.
All told, we think there’s a lot to love in the MasterLiquid Pro heatsinks, and we think builders will feel the same way. We’re happy to send the $120 MasterLiquid Pro 240 home with a TR Recommended award for its stock-clock cooling prowess and its decent overclocking chops. For those who want similar overclocking headroom and even lower noise levels, the $130 MasterLiquid Pro 280 excels—and it gets a coveted Editor’s Choice award to show for it.