For those of you that are curious as to some of the reasoning and equipment behind our PSU testing program here at TheFPSReview, we have put together an introduction for you that shares a lot of the behind the scenes of the program. This program is based on what the author developed at [H]ardOCP and utilizes the equipment bequeathed to the author by Kyle Bennett. The testing we are conducting today is exactly as described in that document and will continue with our Transient Testing.
Transient Test 1
Test #1 is equal to approximately 25% of the rated capacity of the GIGABYTE P750GM at 45c. This makes Test #1 equal to 184W by loading the 12v rail to 13a, the 5v rail to 2a, the 3.3v rail to 1a, the +5vsb to 2a, and the -12v to 0.3a before the addition of the transient load. The results of Test #1 show a ~600mV drop on the 12v rail and ~70mV drop on the 5v rail when each is directly loaded. At the same time that the load was being triggered on the 12v rail, the 5v rail measured a ~65mV drop.
Transient Test 2
Test #2 is equal to approximately 50% of the rated capacity of the GIGABYTE P750GM 750W at 45c. This makes Test #2 equal to 367W by loading the 12v rail to 27a, the 5v rail to 4a, the 3.3v rail to 2a, the +5vsb to 2a, and the -12v to 0.3a before the addition of the transient load. The results of Test #2 show a ~475mV drop on the 12v rail and ~55mV drop on the 5v rail when each is directly loaded. At the same time that the load was being triggered on the 12v rail, the 5v rail measured a ~40mV drop.
Transient Load Testing Summary
The Transient Load Tests results for the GIGABYTE P750GM are passing but not impressive. In today’s testing, the P750GM saw the loaded 12v rail post a peak change of ~600mV, and the loaded 5v rail post a peak change of ~70mV! The unloaded 5v peak change during the 12v load was ~65mV. Those numbers are, in an absolute sense, terrible. In a relative sense, this unit was worse than the ASUS ROG STRIX 750W, Phanteks AMP 750 and EVGA SuperNOVA G5 750W. Indeed, relative to those units the P750GM is not even competitive. So, passing (barely I might add) does not mean good. Let’s move on now to see how this unit does in the DC Output Quality aspect of our testing!