In the following table the Legacy timings are for PSUs designed before 2020. For PSUs made in 2020 the Required column is in effect and the third column has the recommended timings for ALPM support.
Intel recommends that PSU manufacturers should label or provide at least information on the PSU timings T1 and T3, to allow mainboard manufacturers to optimize the turn-on time.
PS_ON# – REQUIRED
The PS_On signal's characteristics remain the same. See the table below, but there is a change here to support systems with ALPM. The PSU might be asked to turn back on immediately after it goes to standby so that voltage rails won't be zero. The new ATX spec states that the PSU must turn back on in such a scenario and, more specifically, after 100 ms of a PS_ON command to go to turn off.
Low Load Efficiency
The low-load efficiency requirements are easier to follow now. PSUs with 500W capacity or less are tested with a 10W load while higher capacity PSUs are tested with a 2% load. In all cases, the PSUs must have above 60% load (required), while it is recommended to have above 70%.