Comparison Cougar STC STC 500 vs Cougar XTC XTC500

The maximum current that the PSU is capable of issuing + 5Vsb to the power line.

For more information about power lines in general, see "+3.3V". Specifically, the + 5Vsb line is used to power the computer electronics in standby mode, when the main and only task of the system is to respond to pressing the power button. This does not require high power, so this figure rarely exceeds 3A.

PC PSU dimensions are defined by the form factor (most often ATX 150×86 mm), and the key factor in compatibility is depth — the PSU case length. “Universal” ATX units are usually 140, 150 mm, while quiet, high-power models with large heatsinks and a 135/140‑mm fan range from 160 to 200+ mm; compact builds use SFX/SFX-L (depth ~100 and ~125 mm with an adapter bracket). The greater the depth, the higher the risk of hitting drive cages, the PSU shroud, cable management, or a front LCS radiator, and modular connectors plus cable bend radius require another 20 – 40 mm of real clearance.