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

This image is the blank background control test on an unused connector from our SM-8800 during the testing of the SilverStone ST1000-PTS. 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 SilverStone ST1000-PTS at 45c. This makes Test #1 equal to 264W by loading the 12v rail to 20a, the 5v rail to 2a, the 3.3v rail to 1a, the +5vsb to 2a, and the -12v to 0.3a. The SilverStone ST1000-PTS is starting off in decent shape. The 12v rail is peaking at ~15mV of ripple/noise while the minor rails are peaking at less than ~10mV of ripple/noise.

120v Input

100v Input

Test #2 is equal to approximately 50% of the rated capacity of the SilverStone ST1000-PTS at 45c. This makes Test #2 equal to 484W by loading the 12v rail to 38a, the 5v rail to 3a, the 3.3v rail to 2a, the +5vsb to 2a, and the -12v to 0.3a. Test #2 sees only minor changes as the 5v and 3.3v rails are coming in at ~10mV of ripple/noise while the 12v rail is coming in at ~25mV of ripple/noise.

120v Input

100v Input

Test #3 is equal to approximately 75% of the rated capacity of SilverStone ST1000-PTS at 45c. This makes Test #3 equal to 732W by loading the 12v rail to 58a, the 5v rail to 5a, the 3.3v rail to 4a, the +5vsb to 2a, and the -12v to 0.3a. Test #3 sees the 12v rail move up to ~35mV of ripple/noise. The 3.3v rail is coming in at ~10mV of ripple/noise again while the 5v rail hits ~20mV of ripple/noise.

120v Input

100v Input

Test #4 is equal to approximately 100% of the rated capacity of the SilverStone ST1000-PTS at 45c. This makes Test #4 equal to 977W by loading the 12v rail to 80a, the 5v rail to 4a, the 3.3v rail to 2a, the +5vsb to 2a, and the -12v to 0.3a. In the final regular test, we see the 12v rail peaking at ~35mV of ripple/noise while the minor rails are peaking at ~10mV of ripple/noise (5v rail) or ~15mV of ripple/noise (3.3v rail).

Torture Test

The Torture Test is equal to approximately 80% of the rated capacity of the SilverStone ST1000-PTS at 45C. This makes the Torture Test equal to 792W by loading the 12v rail to 62a, the 5v rail to 7a, the 3.3v rail to 5a, the +5vsb to 2a, and the -12v to 0.3a. At the end of the Torture Test, we see the 12v rail peaking at ~25mV of ripple/noise while the 5v and 3.3v rails are peaking at ~10mV of ripple/noise.

DC Output Quality Summary

The overall DC Output Quality of the SilverStone ST1000-PTS is good overall. The ripple/noise values started the day off in good shape and only grew slightly from there. Overall, the ST1000-PTS ended up posting a peak trace amplitude on the 12v rail of ~35mV followed by ~20mV on the 5v rail and ~15mV on the 3.3v rail. None of these values exit the ATX12v specification limits and the worst relative value only hit ~40% of the ATX12v specification limit. In addition to that, this unit is a much smaller 1000W unit than we normally see so it also has some special constraints on design. Overall then, this unit did well and, while it won’t be the absolute best 1000W unit on the market in this regard, it is more than serviceable. Let’s move on now and see how all of this wraps up!

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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...