DC Output Quality

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 examination of the DC Output Quality.

Control Test Graphing

GIGABYTE P750GM 750W Power Supply Control Test Graph
ASUS ROG STRIX 750

This image is the blank background control test on an unused connector from our SM-8800 during the testing of the GIGABYTE P750GM. This lets us determine what the background noise looks like during testing.

120v Input

100v Input

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. The GIGABYTE P750GM is starting off in good(ish) shape. The 12v rail is peaking at ~20mV of ripple/noise and the minor rails are peaking at less than ~10mV of ripple/noise on the 5v rail and ~15mV of ripple/noise on the 3.3v rail.

120v Input

100v Input

Test #2 is equal to approximately 50% of the rated capacity of the GIGABYTE P750GM 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. Test #2 sees only minor changes as the 12v rail is coming in at ~20mV of ripple/noise while the 5v and 3.3v rails are coming in at ~10mV of ripple/noise.

120v Input

100v Input

Test #3 is equal to approximately 75% of the rated capacity of GIGABYTE P750GM at 45c. This makes Test #3 equal to 573W by loading the 12v rail to 42a, the 5v rail to 7a, the 3.3v rail to 5a, the +5vsb to 2a, and the -12v to 0.3a. Test #3 sees the 12v rail peaking at ~25mV of ripple/noise while the minor rails are coming in at ~10mV of ripple/noise.

120v Input

100v Input

Test #4 is equal to approximately 100% of the rated capacity of the GIGABYTE P750GM at 45c. This makes Test #4 equal to 752W by loading the 12v rail to 60a, the 5v rail to 2a, the 3.3v rail to 1a, the +5vsb to 2a, and the -12v to 0.3a. In the final regular test, we see the 12v rail peaking at ~30mV of ripple/noise while the minor rails are peaking at ~15mV of ripple/noise on the 3.3v and 5v rail.

Torture Test

The Torture Test is equal to approximately 80% of the rated capacity of the GIGABYTE P750GM at 45C. This makes the Torture Test equal to 602W by loading the 12v rail to 44a, the 5v rail to 8a, the 3.3v rail to 6a, the +5vsb to 2a, and the -12v to 0.3a. At the end of the Torture Test, we see the 12v rail peaking at ~20mV of ripple/noise while the 5v and 3.3v rails are peaking at ~15mV of ripple/noise.

DC Output Quality Summary

The overall DC Output Quality of the GIGABYTE P750GM is excellent! The GIGABYTE P750GM ended up posting a peak trace amplitude on the 12v rail of ~25mV followed by ~15mV on the 5v rail and ~15mV on the 3.3v rail during our normal tests. The worst absolute value among these hit well below ~50% of the ATX12v specification limit. In relative terms, this unit was mixed with the Phanteks AMP 750 while matching the EVGA SuperNOVA G5 750W and being slightly better than the ASUS ROG STRIX 750W. So, it seems that this unit is currently competitive among 750W units we have seen in this regard to date! Let’s move on now and see how all of this wraps up!

Paul Johnson

Paul is a long time PC hobbyist and tech enthusiast having gotten his start when he broke his first C64 quickly followed by breaking his first IBM XT. Most notably however, for 12 years, he served as the...

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4 Comments

  1. There’s something therapeutic with reading through a Paul Johnson PSU review – it’s like comfort food for the PC DIY-soul.
  2. Great review Paul. I’ve been reading some good, but mostly bad user reviews about Gigabyte PSU’s. This review is way more clear if someone was considering one of these units.
  3. Great review Paul. I’ve been reading some good, but mostly bad user reviews about Gigabyte PSU’s. This review is way more clear if someone was considering one of these units.

    No doubt you have. They are probably right as well. We definitely didn’t have the best results with this unit and there are known issues with them that we got lucky and did not hit to a degree.

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