be quiet! System Power U9 500W PSU Review: Affordable and Quiet

Why you can trust Tom's Hardware Our expert reviewers spend hours testing and comparing products and services so you can choose the best for you. Find out more about how we test.

Performance, Noise and Efficiency

Performance Rating

Click For More Results

The SU9-500 is between the two most popular offerings in the mainstream category, the EVGA 450 BT and the Corsair CX450.

Noise Rating

The graph below depicts the cooling fan's average noise over the PSU's operating range, with an ambient temperature between 30°C and 32°C (86°F to 89.6°F).

Click For More Results

The be quiet! offering honors the name of its brand, taking over first place in the noise output chart.

Efficiency Rating

The following graph shows the PSU's average efficiency throughout its operating range with an ambient temperature close to 30°C.

Click For More Results

The overall efficiency is high enough, surpassing the corresponding levels of the similar capacity Corsair and EVGA units.

MORE: Best Power Supplies

MORE: How We Test Power Supplies

MORE: All Power Supply Content

Contributing Editor

Aris Mpitziopoulos is a Contributing Editor at Tom's Hardware US, covering PSUs.