DC Output Voltage Regulation
We expected from Intel to throw away the not required, any more, -12V rail but to our surprise it kept it! It is optional yes, but in our opinion it should not be included any more.
The lower limit at +12V on all connectors but the PCIe ones has been changed from -5% to -7% to allow the PSUs to be pass our transient tests with the increased loads that the new ATX spec introduced (200% of the PSU's max capacity for 100μs). This means that the min allowed voltage at +12V is now 11.2V. Intel also states that the nominal voltage on this rail can be increased up to 12.2V to not allow for lower than 11.2V. The voltage tolerances shown in the table above are required on all connectors.
Output Transient Step Sizes
There are some changes in the transient load step sizes, shown in the table below.
Given the new PCIe 5.0 requirements, the step size at +12V3/4 has vastly increased from 80% (Recommended) at up to 300%. The load-changing repetition rate remains the same at 50 Hz to 10 kHz. There is also a significant increase in the slew rate, from 1A/μs to 5.0 A/μs for the +12V rails. If the PSU has 450W or lower capacity it doesn't have 12VHPWR connectors, the slew rate at +12V drops to 2.5 A/μs.
