Be Quiet! Straight Power E9 680W Review

When testing in a power supply laboratory it is difficult to take fan noise readings as the noise from the Chroma corrupts everything. The next best thing in our circumstances was reading off the fan speed with a tachometer to get an idea for the noise. In the Enermax Europe PSU lab we had to do exactly that and we recorded the fan speed at each load scenario. The ambient temperature during testing held constant at 26 degrees, with 1 degree of variation. Each power supply had a consistent time period of 5 minutes to stabilise between each load scenario. 

In my experience the following general relationships apply between noise levels and fan speeds, though it can vary greatly between the type of fan used.

• Below 800 RPM – Inaudible/Silent
• 800 to 1000 RPM – Barely audible
• 1000 – 1200 RPM – Audible but still quiet
• 1200 – 1400 RPM – Moderately noisy
• 1400 – 1800 RPM – Noisy
• 1800 RPM or higher – Intolerable

The Be Quiet Straight Power E9 impressed in the fan speed department. It never exceeded 600 RPM under realistic loads which is dead silent while at 80 and 100% loads it was still near enough silent. Even at 1190 RPM the Silent Wings fan is more or less silent and definitely has a noise advantage over other fans at the same speed.