Transient Testing

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

Loaded/Unloaded

12v/5v

Test #1 is equal to approximately 25% of the rated capacity of the Seasonic FOCUS GM-650 at 45c. This makes Test #1 equal to 171W by loading the 12v rail to 12a, 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 ~360mV drop on the 12v rail and ~105mV 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 ~60mV drop.

Transient Test 2

Loaded/Unloaded

12v/5v

Test #2 is equal to approximately 50% of the rated capacity of the Seasonic FOCUS GM-650 at 45c. This makes Test #2 equal to 322W by loading the 12v rail to 24a, the 5v rail to 3a, 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 ~350mV 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 ~20mV drop.

Transient Load Testing Summary

The Transient Load Tests results for the Seasonic FOCUS GM-650 are passing and generally decent for what this unit is today. In today’s testing, the FOCUS GM-650 saw the loaded 12v rail post a peak change of ~360mV and the loaded 5v rail post a peak change of ~105mV. The unloaded 5v peak change during the 12v load was ~60mV. Those numbers are, in an absolute sense, passing. In a relative sense, this unit is, again, harder to place as we have not seen any other 650W power supplies to date here at TheFPSReview. This unit is one of Seasonic’s mainstream offerings so these results may not seem great for a premium offering, but they do seem to be in line with this more moderate position in the product stack. Let’s move on now to see how this unit does in the DC Output Quality aspect of our testing!

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...

Join the Conversation

3 Comments

  1. As always, an excellent review Paul!

    Nice little PSU. I don’t mind the "semi"-modular design of it either. You’re going to be hooking up the ATX and ATX Power cables anyways, no real reason they have to be modular.

  2. Nice review. I’m running a 550W Seasonic Focus PSU in my wife’s PC here with no issues, and decided to go with the 1000W Seasonic in my main PC which has also been rock solid. Always liked their warranties.
  3. Nice little PSU. I don’t mind the "semi"-modular design of it either. You’re going to be hooking up the ATX and ATX Power cables anyways, no real reason they have to be modular.

    Does make installation / cable management a bit easier when you have a bit more flexibility in routing by virtue of having both ends free, but yeah, your going to use them no matter what.

Leave a comment