The Be Quiet! Pure Rock 2 FX CPU Cooler Review: For Quiet Contemplation

Testing Results, Maximum Fan Speed

To begin with, we are having a look at the Be Quiet! Pure Rock 2 FX with its stock 120 mm fan running at its maximum speed.

Overall, the performance figures we received from the Pure Rock 2 FX were not far from other similarly-sized products. With an average thermal resistance of 0.1436 °C/W, the Pure Rock 2 FX lands very close to most single-array 120 mm fan tower coolers, such as the Noctua U12A and the Cooler Master EVO 212. It has a relatively steady thermal profile, with the thermal resistance reaching its optimum value with a load of exactly 150 Watts, the design power of this cooler.

Be Quiet!’s main focus is quiet operation, and the Light Wings fan does a fairly good job at it. Although the 37.1 dB(A) that we record with the fan running at its maximum speed is definitely not absolutely quiet, it is a very low figure for a fan running at 2000 RPM. The Light Wings fan is audible at maximum speed but the noise pressure level ought to be tolerable for the vast majority of users, even in a very quiet environment.

Testing Results, Low Fan Speed

In this test we are switching things up a bit, taking a look at the cooler’s performance with the Light Wings fan taken down to half speed.

The reduction of the fan’s speed to 1000 RPM naturally has a negative impact on the thermal performance of the Pure Rock 2 FX cooler, yet that impact is lesser than we anticipated. The average thermal resistance of 0.1812 °C/W is now better than that of most similarly sized CPU coolers, with only the dual fan Noctua NH-U12A and NH-U12S + NA-FK1 coolers managing to outperform it. What gives the Pure Rock 2 FX this performance edge is the speed of the Light Wings fan, which is higher than most other coolers in this test.

Reducing the speed of the Light Wings 120 mm fan down to 1000 RPM makes the Pure Rock 2 FX cooler practically inaudible. With a sound pressure reading of 32.3 dB(A) at one meter, it should be nearly impossible to notice the cooler unless you're in a dead-silent room.

Thermal Resistance VS Sound Pressure Level

During our thermal resistance vs. sound pressure level test, we maintain a steady 100W thermal load and assess the overall performance of the coolers by taking multiple temperatures and sound pressure level readings within the operating range of the stock cooling fans. The result is a graph that depicts the absolute thermal resistance of the cooler in comparison to the noise generated. For both the sound pressure level and absolute thermal resistance readings, lower figures are better.

This chart reveals the standing of the Pure Rock 2 FX cooler against its direct competition. It delivers about the same thermal performance as the Noctua NH-U12S and the SilverStone Argon AR07, yet at either a louder or a quieter noise level respectively. Other similarly sized coolers seem to have lower thermal performance over the same noise levels.