Protection Features Evaluation

All rails have high OCP triggering points, especially the minor ones. There is no need for more than 30 A on the 3.3 V rail, especially in a passive PSU with no heatsinks on the FETs that regulate this rail. Overpower protection is also set high, but all parts Seasonic used are overrated. Finally, over temperature protection is set high because this is a passive PSU, so it is expected to have high internal temperatures.

DC Power Sequencing

According to Intel's most recent Power Supply Design Guide (revision 1.4), the +12 V and +5 V rails must have voltages equal to or greater than the +3.3 V rail's output at all times. For our first measurement, we turn the unit off and switch it back on without a load on any of the rails.



The 3.3 V rail is always at a lower voltage than the other two rails, but there is a problem in the PSU OFF to Full Load test since all rails drop in voltage because the minor rails are generated through +12 V. This is a major issue Seasonic should address, the sooner the better. I have tested several samples of the same model, and all of them had the same issue.

EMC Pre-Compliance Testing - Average and Peak EMI Detector Results

Electromagnetic Compatibility (EMC) is the ability of a device to operate properly in its environment without disrupting the proper operation of other close-by devices.

Electromagnetic Interference (EMI) stands for the electromagnetic energy a device emits, and it can cause problems in other close-by devices is too high.


EMI emissions are low. The PSU's EMI filter does a decent job.