The Zalman PSU is relatively expensive at Â£89.30, but is particularly well suited to building quiet PCs since it can control the internal cooling fanâ€™s speed depending on the temperature inside the power supply. As well as P4 and SATA connectors, the ZM400B-APS also comes with a very useful multi-connector that can be used to supply +5V or +12V power to up to four fans with three-pin connectors.
With the new power supply installed, the reduction in noise wasnâ€™t quite as impressive as before. Our sound level meter only registered a 1dB(A) drop in overall noise level. However, the fan noise from the PSU was now no longer audible over the lower frequency hum coming from the two 120mm case fans. I could also hear some higher frequency noise coming from the 60mm CPU cooling fan inside the case, and possibly from one or both of the smaller fans on the motherboard or graphics card.