The device tag on the Silverstone ST56ZF doesn't do its own numbers very well (there's no good summary table as on other tags you see elsewhere in this story).

We had no problems with the Silverstone ST56ZF in our testing. It survived our 12-hour endurance test without a whimper. The voltages were very stable across the board, but under heavy load they dip somewhat below nominal values - but even so, they remain within specification tolerances.

The device does earn good marks for efficiency ratings: It measured out at 82.3%, 84.5% and 83.8% for our three load classes (minimal, 50%, peak load). With nearly equal values across the entire load spectrum, this is just what a good PSU is supposed to deliver.

Prices for this unit range from $130 to $140; given its rated performance and high efficiency, we think this is fair.

Retail packaging for the ST56ZF