Noise levels
We measured noise levels 1" from the ST20G5's front, side, and rear using an Extech Model 407727 Digital Sound Level Meter. Measurements were taken after 10 minutes at idle, and then after another 10 minutes of a Folding@home CPU load. We also measured the noise levels of Shuttle's XPC models SN25P, SB95P V2, and SB86i for comparison. The SN25P was equipped with identical hardware to the ST20G5, while SB95P V2 and SB86i were equipped with a Pentium 4 520 2.8GHz processor and Radeon X600 XT graphics card. The ST20G5, SN25P, and SB95P V2 used their default Smart Fan setting, but the SB86i requires its Mid fan speed setting to maintain stability under load.

With graphics handled by the IGP, the ST20G5's noise levels are impressively low. However, the SN25P's noise levels are lower when a graphics card is installed.