Before overloading power supplies we always test first if the over current protection (OCP) circuit is active and at what level it is configured.

In order to do that we increased current on the +12V2 rail until the power supply shut down. This happened when we tried to pull more than 20 A from it.

Manufacturers always leave a margin between what is written on the label (18 A in this case) and the level the OCP circuit is really configured (20 A in this case). We always like to see this margin as tight as possible, like happened with this power supply.

Then starting from test five we increased currents to the maximum we could with the power supply still running inside ATX specs. The results are below. If we tried to increase one amp on any of the outputs a protection would enter in action, shutting down the power supply. Nice.