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Four Closed-Loop CPU Coolers Take On Noctua's NH-D14

Cooling, Fan Speed, And Noise

Our biggest concern with sealed liquid coolers isn’t leaks, but the fact that they don't help dissipate the heat that builds up on a motherboard's voltage regulator circuitry. At one time, those components required a fan nearby when they were operating under a heavy load. Even now, airflow over power logic is a good idea. I’ve recommend devices like Antec’s Spot Cool for many years to combat hot spots, but part of today’s evaluation will focus on how each cooler performs without help.

Corsair’s H100i jumps out of the gate with a fairly significant cooling advantage, going so far as to match the NH-D14 when we look at voltage regulator temperature. With that said, all top-mounted radiators are going to an advantage over Zalman's LQ320 on our test bed. This is because the heat sink covering our motherboard's power circuitry is mounted directly beneath the case’s furthest-back top panel fan.

Remember how we modified the ELC240 with little washers so that its springs would pull tighter to the motherboard? Well, the chart above demonstrates that we didn't make any other changes to fan speed, while the chart at the top of this page illustrates how much more effective our little tune-up made Enermax's solution.

The ELC240 has the second-slowest fan speed, behind our air-cooling reference point, and the correspondingly-lower airflow explains why its temperatures are the highest of all liquid coolers.

Acoustics are different in every case you use, so we're including the noise levels of bare coolers, outside of a case. Unfortunately, that’s not a realistic test scenario for the H100i, since its smart controller spins down almost completely when there is no heat source. Don't worry though; we're using the full system noise levels for our final evaluation.

Lower fan speeds typically result in higher temperatures and less noise, but there's no direct scale between those three variables. Instead, the speed at which a fan achieves its optimal flow-to-noise ratio is based upon the shape of its fins. The ELC240’s low fan speed produces relatively little noise, but its acoustic advantage among liquid coolers appears smaller than its thermal disadvantage. Alternatively, full speed appears to be above the Seidon 240M's optimal RPM, with noise disadvantages exceeding cooling advantages. Cooling-to-noise is going to be a big consideration in our performance analysis.

Thomas Soderstrom is a Senior Staff Editor at Tom's Hardware US. He tests and reviews cases, cooling, memory and motherboards.