Best Closed-Loop Liquid CPU Coolers
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Liquid cooling attempts to circumvent heat sink size limits by moving the largest portion of the cooler away from the CPU socket to a dedicated spot on the case. Relocating the radiator to the case also allows it to accept cooler air from outside the case, particularly when it's mounted to the front panel. Even a radiator mounted to the top panel to serve as an exhaust system usually benefits from the unit's larger size. Furthermore, displacing cooler weight from the CPU socket to the case decreases the damage risk associated with rough handling of the complete system, making closed-loop liquid coolers a better choice for those who must transport or ship a machine.
We still define performance as the best ratio of cooling to noise.
The performance of open-loop coolers varies widely depending on the builder's configuration choices, and most are sold as individual components or base kits designed for further customization. Reliability of these systems is dependent upon installation skill or, as was the case with newsman Niels' first installation, making sure everything fit and was connected properly.
Closed-loop designs seal the liquid inside to prevent leaks and reduce maintenance, while open loops allow builders to cool multiple components from a single radiator. Beyond being suitable to more builders for the lack of leaks, a lack of customization makes closed-loop coolers easy to rate. While larger coolers tend to provide better performance, different models of the same or similar radiator size can perform dissimilarly based on materials, cooling fin and water channel design, fan design, pump design and the speed of those moving parts.
Combining the flexibility of removable hoses with integrated reservoirs, hybrid loop kits ship sealed from the factory, but can be opened by enthusiastic builders to add additional components. We test these in the same manner as closed loop coolers.
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Best Liquid Coolers
2/16/2018 Update: added the EVGA CLC 280 RGB, the Cooler Master Master Liquid ML240L (earned an Editors’ Choice award), and the Thermaltake Floe Riing RGB 360 TT Premium Edition (earned an Editors’ Choice award).
10/25/2017 Update: added the ID-Cooling Auraflow 240 (earned a 2017 Approved award).
8/17/2017 Update: reviewed the Alphacool Eisbaer 360 (no award, not listed).
5/11/2017 Update: added the Fractal Design Celsius S24 (earned a 2017 Approved award).
Cooler Master MasterLiquid ML240L
Thermaltake Floe Riing RGB 360 TT
ID-Cooling Frostflow 240L
Arctic Liquid Freezer 240
Fractal Design Celsius S24
Deepcool Gamer Storm Captain 120EX
1.1" (2.2" w/fans)
1.0" / 25.4mm (2.25" /57.15mm w/fans)
1.1" (2.2" w/fans)
1.1" (2.2" w/Fans)
1.5" (3.6" w/fans)
1.2" (2.2" w/fans)
1.1" (2.2" w/fans)
1.1" (2.0" w/Fan)
5.125" / 130.18mm
Best Flat-Out Thermals: Corsair H115i & EVGA CLC 280
Buy the Corsair H115i here or EVGA CLC 280 here.
Find our EVGA CLC 280 review here.
You might call this an award for the best “out-of-the-box” thermals. For this one, we’re ignoring the noise argument and just looking at a baseline of raw thermal performance when maxed-out. Both the Corsair H115i and EVGA CLC 280 rank within margin of error from one another, functionally tying for the top of the chart. These are 280mm solutions, which we think provide an ideal mix of compatibility and noise-to-thermal performance, when min-maxed for each metric. In most cases, 280mm coolers are an extra $10-$20 over their 240mm counterparts, and the additional thermal headroom means that fans can be slowed down in turn, achieving similar thermal performance to 240 solutions, but with lower noise levels. As for the highest raw performance, though, the Corsair and EVGA 280mm solutions both take half of the crown.
Each unit uses an Asetek Gen5 pump, with the two tying for price at $110 on sale this week, or typically around $130. Regardless of the sale prices, EVGA and Corsair seem to constantly match one another, so the choice will primarily come down to what you think of the pump block design. Internally, they’re mostly the same; in this case, it’s the outside that counts. Both units have RGB LEDs behind the logo plates, and both have their own software solution that you can hook into.
Best Noise-to-Performance: NZXT Kraken X62
Buy the NZXT Kraken X62 here.
Find our NZXT Kraken X62 review here.
Strictly looking at out-of-the-box fan configurations, because aftermarket fans would basically equalize all of these, the crown for peak noise-normalized performance thus far goes to the NZXT Kraken X62. We haven’t tested as many coolers with this newer method, but so far, the stack-up of popular coolers puts NZXT’s RGB-happy cooler up top.
The Kraken X62 also happens to be one of the most expensive coolers on the market, and is sometimes difficult to get ahold of outside of the NZXT store. Fortunately, other nearby coolers, including 360mm units, can compete in price and performance with the Kraken X62.
Most Serviceable: Enermax Liqtech TR4 360
Buy the Enermax Liqtech TR4 360 here.
Find the Enermax Liqtech TR4 review here.
This next award is for “Most Serviceable,” and is assigned for being the easiest cooler to take apart and maintain over a long service life. Enermax was first to market with an actually good liquid cooler for Threadripper, one which we found highly competitive in noise-normalized performance, but also trivial to dismantle and maintain. The company nearly deserves its own award category for being brave enough to invest in a small market segment, because it’s paying off when considering the performance uplift granted by a full-coverage coldplate. The Liqtech TR4 outstrips Asetek performance significantly, and opening the unit reveals more of why: The cooler spans its microfins nearly across the entire area of the coldplate, leveraging the native surface area of Threadripper for cooling benefit.
But the serviceability of the cooler gives it an important award. In our tear-down, we show how easy it would be to maintain the Liqtech TR4 in the future. Permeation will be less of a concern, as easy-access ports make refilling a non-issue, if it’s ever used beyond the 4-5-year mark. Block design and assembly are also surprisingly high-quality, making the Liqtech units the only coolers we’re strongly recommending for Threadripper, outside of the Noctua air NH-U14S.
Most Modular: Alphacool Eisbaer 420
Buy the Alphacool Eisbaer 420 here.
For Most Modular, we have the Alphacool Eisbaer 420. This is an odd unit, admittedly, and that’s for a few reasons: Thermally, the Eisbaer performs worse than many of its smaller, cheaper peers, which is entirely due to its stock Eiswind fans. The fans are noise-focused and limited in performance, leaving us wanting. Replacing the fans helps a bit, though you can potentially become bottlenecked on the pump with a radiator this large.
Still, the unit can hook into pre-filled Alphacool blocks, like the Eiswolf that we previously reviewed, and give users what amounts to a cheaper, semi-open loop. The market is small for this setup, as venturing into modular quick disconnect territory does quickly near open loop markets, but there is a market for it. The Eiswolf blocks can cool reference GTX 10 series cards, have an integrated pump to help ensure that the 420’s pump doesn’t limit performance, and are also pre-filled. We weren’t big fans of the quick disconnect valves, but they get the job done – just be careful to unscrew the correct end of the valve and read the instructions thoroughly. In terms of modularity, short of going with an EK Fluid Gaming beginner’s open loop kit, the Alphacool options provide full copper solutions worth considering for niche markets. We do recommend replacing the fans, though.
Best Noise Levels: EK Predator 280 XLC (RIP)
This Best Noise Levels award goes to a cooler that’s been retired, sadly, and has been replaced with other lines. We give this one to EK for the EK Predator 280 XLC cooler, which managed to remain operable and within temperature spec at just 600RPM, while putting out a 29.2dBA noise level – that’s just 3dBA over our noise floor. Temperatures were around 49C delta T over ambient for this cooler – so nearing 70C, if you factor-in ambient, and remaining completely operable under a full AVX workload, but also completely silent. At this noise level, the cooler remains less audible than other system noise generators, like power supply, GPU, and case fans.
We were also impressed with EK’s quick disconnect system, at first, as they are easily the best of their kind when it comes to ease-of-use and security. The Predator unit’s stock fans permit lower operating noise levels, greater range of customization, and competitive stock thermals.
Unfortunately, the cooler had good reason to be terminated: Just one scroll through the Newegg user reviews reveals nearly 70% negative reviews, all of which point toward leaks in the loop. We still want to call attention to the fan and cooler design for its silence, largely in hopes that one of the other CLC makers can replicate the acoustic performance without also replicating the destroy-everything performance.
Best Overall Value: EVGA CLC 240
Buy the EVGA CLC 240 here.
Read the EVGA CLC 240 review here.
The next award, “Best Overall Value,” was originally expected to go to the Cooler Master Master Liquid 280, but we never got to test it. The cooler’s fan screws have a tolerance of 50.46 to 50.65mm, and because Cooler Master routes its radiator tubes right behind the screwhole, and additionally does not have a stopper pad (like every other cooler on the market), the 50.65mm screw punctured the tube. Fortunately, no damage was caused to the test system, and looking at user reviews online, it appears we weren’t alone in this problem. This is a matter of zero-tolerance and zero redundancies or safeties provided by the radiator. Of the dozens of units we’ve worked with, this is the only one to ever have this problem.
Let’s give the award to something more deserving.
The Best Overall Value presently goes to the EVGA CLC 240 cooler, which was bitterly embattled with the Corsair H100iV2. Looking at overall performance versus the price, including noise-normalized 40dBA performance and flat-out performance, the EVGA CLC 240 slightly outperforms the H100iV2 at 40dBA, and manages otherwise similar performance. The point of differentiation is that, presently and generally speaking, EVGA has held onto a slight price lead over Corsair. The coolers both bounce between $85 and $110, with EVGA a couple bucks cheaper right now.
The trouble with value liquid coolers, as always, is that you rapidly enter territory where an air cooler might be cheaper and equivalent in all key performance metrics.
Dumbest Trend: Bad Fans
The worst trend across nearly all liquid coolers is that of bad fans. The cooler companies have to cut corners somewhere to better compete with air. For Cooler Master, that’s radiator design, resulting in catastrophic failure. EK did the same with its Predator cooler, unfortunately. The wiser companies cut back on fans, but produced reliable, non-leaking products that have proven safe to use and of high performance potential – they’re just limited by fans, in many instances. We’d like to see better fans used in the future, though that will spike the price at least a few dollars at each form factor.
That’s all for this round-up. More to come soon.
Editorial, Testing: Steve Burke
Video: Andrew Coleman