One of the liquid coolers in today’s comparison looks like it runs extra cool, while another model operates very quietly. In order to compare cooling to noise, we first take mathematical averages of the CPU temperature delta for all coolers and the noise level for all coolers. Changing to a percentage scale, we reflect higher thermal performance for lower temperatures (an inverse scale) by dividing the group average by each cooler’s actual temperature.
Larger denominators produce smaller percentages (one-eighth is half as much as one-fourth), so we put noise on a direct scale by dividing each cooler’s installed noise by the group’s average. Dividing the first calculation by the second produces an easy-to-read cooling-to-noise chart.
Nothing is more than 100% efficient, so we change the 100% baseline to 0% by subtracting 100% from each calculation. We see, for example, that Noctua’s NH-D14 is 22% more efficient than the average for today’s cooling contenders, while Cooler Master's Seidon 240M is 7% less efficient than the group average.
Corsair’s performance is a little harder to peg, since its automatic controller was tested at both default and maximum settings. Because the cooler operates in default mode right out of the box, we consider its higher (Auto) configuration as the second-place finisher among liquid coolers in Acoustic Efficiency. Zalman's LQ320 edges out the H100i in this chart.
Compared to the $120 dual-fan liquid cooling competition, Cooler Master's $100 Seidon 240M looks like a great value. Zalman's single-fan cooler takes second place, though we also have to consider that the design of its LQ320 resulted in excessively-high temperatures from our voltage regulator circuitry (only CPU temperatures are used in our calculation).
But there's a good reason not to fold in the power logic's thermal results. The heat sink our motherboard uses to cool its VRM is found along the top edge, putting top-mounted radiators at an advantage. Many platforms, however, have voltage regulation logic between the processor interface and rear I/O ports, favoring rear mounted radiators like Zalman's and/or air coolers like the NH-D14. Other motherboards have voltage regulators in both places.