The Fractal Design Celsius S24 & S36 AIO Coolers Review

Testing Results, Maximum Fan Speed

Starting things off, let's take a look at cooler performance with the fans at their full, 12 V fan speed.

Our concurrent testing of the two Celsius variants gave us some very interesting results. With their fans running at their maximum rated speeds, the performance of the Celsius S24 is not record-breaking, yet it definitely is competitive, especially when taking the lower noise figures into account. The average thermal resistance of the Celsius S24 is 0.082 °C/W, which is slightly higher than that of most other dual 120 mm fan coolers, but our sound pressure meter was also recording only 38.7 dB(A) at the time of the test, which is the lowest figure that we have recorded up to this date from any comparative AIO cooler.

Comparing the performance of the Celsius S24 to its larger S36 is not as straightforward as most people would assume. Despite its significantly greater mass, the S36 delivers virtually the same performance at lower load levels. As the load increases, the performance gap between the two coolers widens slightly, but only at very high power loads does the S36 display a true performance advantage. Ultimately, the average thermal resistance of the Celsius S36 is slightly better, at 0.0797 °C/W, but only because of its ability to handle very high thermal loads more efficiently. Meanwhile, the noise level rises to 40.6 dB(A), diminishing the thermal performance gains even further.