be quiet! Pure Loop 280 mm Liquid CPU Cooler Review

An Affordable AiO From A Familiar Name

Adding to the ever-growing collection of CPU cooling options from be quiet! is the new Pure Loop, a line of AiO liquid coolers available in sizes ranging from 120 mm to 360 mm that are reasonably priced – from $84.90 – $119.90 USD depending on size.

A true AiO (all-in-one) liquid cooler rather than a CLC (closed-loop cooler) thanks to a handy fill port, the Pure Loop offers an interesting take on the concept with a pump assembly located inline on the hoses, rather than the block assembly.

Obviously companies must be creative to avoid infringing on Asetek patents, and the performance from this inline pump design will be interesting to examine. Another aspect of the design is the low-key white LED lighting, with no RGBs in sight.

Features from be quiet! For the Pure Loop series:

• Silent and Reliable Cooling: Pure Loop water cooling units have a doubly decoupled pump to guarantee minimal vibration. Up to three Pure Wings 2 fans feature nine airflow-optimized fan blades that ensure a perfect cooling airflow and very quiet operation
• Eye-Catching: The all-black design guarantees the Pure Loop to look stunning in every PC case. The white LED on the cooling block underlines the stylish claim
• Easy and Convenient Handling: An easy-to-access refill port simplifies the refilling process and makes handling very convenient Flexible sleeved tubes guarantee a simple mounting
• Outstanding Service and Support: 3-year manufacturer’s warranty. Product conception, design and quality control in Germany

Cooler Design

While adhering to a conventional all-in-one loop concept, the Pure Loop 280 mm offers a couple of key points of differentiation – which we will get to in a moment.

The CPU block offers a nice brushed aluminum look with a simple be quiet! logo and subtle illumination via a white LED ring – there are no RGB effects.

The base of the cooler is copper with a nickel finish, and it appears nicely milled for a flat mating surface.

We received the 280 mm version, and the radiator is of the usual aluminum variety with a black finish.

And now for the first differentiation point, as the radiator includes a fill port along one side – no closed loop here.

be quiet! includes 100 ml of coolant to top off the cooler and keep it performing like new, and you shouldn’t have to use for the first couple of years. We’ve seen coolant bottles like this included with Enermax designs before, and it’s good to see be quiet! offering a cooler that can be maintained easily.

Next we have the biggest differentiation point: the pump!

Yes, that is the pump, suspended inline on the hoses just below the radiator. be quiet! calls this a “doubly decoupled pump” design, and says this implementation offers “quiet operation and minimal vibration”. It certainly is interesting to think of the vibration resistance of such a suspension, as of course typical Asetek designs place the pump above the cold plate.

Update – 10/15/20: I have been informed that a similar intra-hose pump assembly can be found from Enermax with their LIQFUSION and RAIJINTEK with their ORCUS liquid coolers. I have not been following the AiO industry closely enough, apparently!

Installation

Because I’m a practical (read: boring) person, I chose to install the Pure Loop cooler on the same Intel Z490/i9-10900K platform used for other recent liquid cooler reviews – a choice which will certainly go over well with AMD Ryzen enthusiasts. Why do this? For that sweet unlimited 200W CPU power draw!

The above nonsense aside, the Pure Loop includes everything you need to mount to Intel or AMD desktop systems (no Threadripper support), and I found the hardware kit to be above average (I find things like the rubber rings that hold the retention bolts in place on the base plate to constitute “above average”).

Needless to say, the cooler installation was a snap, and the mount offers quite a bit of mounting pressure – which bodes well for results from the toasty i9-10900K beneath.

Thermal and Noise Performance

Attached to our Intel Z490 test platform with its Core i9-10900K processor – and with the motherboard configured to ignore CPU power limits and use a “standard” fan profile – we got started on some benchmarking.

Before looking at the performance comparison with other coolers, here’s a look at the result from a blender workload, with data recorded via HWINFO64 during a Blender Classroom CPU cycles render:

Max temp in a ~21.5 °C room was 77 °C, which is an excellent result. Another sign of efficient cooling is what I like to think of as the “round trip” from ambient to load, and back again. Notice from the chart how quickly the cooler returns to essentially pre-load temps (in this case it started as 26-27 °C, and ended up at 28-30 °C after the benchmark).

And now for another look at this result with the CPU power draw added in:

When you see power draw consistently above 200W – even approaching 220W at times – from the Core i9-10900K in its unlimited state (which is the default situation for every Z490 board I’ve tested so far) you might appreciate that 77 °C result a little bit more.

And now for some context, with the charts to follow adding results from this test configuration – with the exact same i9-10900K with no power limits enforced.

The 280 mm version of the be quiet! Pure Loop tested very well, finishing between the H115i RGB Platinum and Gamer Storm Castle 280EX – an effective tie when a realistic +/- 1°C margin of error is factored in. Results in the delta 55-56°C range like this are outstanding – but how were noise levels?

Here the Pure Loop finishes in second place in the group, but with load temps 10 dBA above the H115i “Balanced” preset results it’s not particularly quiet – when the fans are allowed to spin up to 100%, anyhow. Those impressive Corsair numbers did come with a restricted RPM fan profile, which also resulted in the highest temps in this group.

At full speed (1600 RPM) the Pure Wings 2 140mm PWM high-speed fans produce quite a bit of wind noise through the radiator, and with some fan curve tweaking the Pure Loop could be a lot more quiet than 44.8 dBA – though temps would be higher, naturally.

Conclusion

With the Pure Loop be quiet! has produced a solid liquid CPU cooler to compliment their lineup of air coolers, entering the market with some very reasonable prices. Fans can get a little noisy at full speed, but that can be controlled with fan curves if it’s a problem.

List pricing for the 280 mm version we reviewed is $104.90 USD, making it one of the most affordable “name-brand” options on the market. And be quiet! is giving these Pure Loop coolers a 3-year warranty, which – along with the refill port and included coolant – suggests that these could end up being a reliable option down the road.

Bottom line: the be quiet! Pure Loop 280 mm liquid cooler we tested looks great, cools very well, and offers excellent value. Recommended.