As in the performance. That is, what is the question here?

A PSU has many aspects as noted at,26.html

There are so many supplies that we tend to pick them at our shop without much to do. Most of the time we select them for price and how much power we need. If a rig is going to demand 500 Watts peak, we'll fit the usual 1,000 Watt PSU. Some folk may try lower values but that's the tip of the ice berg in the selection criteria. We'll also do a quick calculation to be sure any single rail has 50% or more spare Amperes.