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]ard|OCP 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 EVGA N1 750. 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 N1 750 at 45c. This makes Test #1 equal to 185W 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 N1 750 is starting off in ok shape. The 12v is peaking at ~35mV of ripple/noise and minor rails are peaking at ~10mV of ripple/noise.
120v Input
100v Input
Test #2 is equal to approximately 50% of the rated capacity of the N1 750 at 45c. This makes Test #2 equal to 366W by loading the 12v rail to 27a, the 5v rail to 7a, the 3.3v rail to 5a, the +5vsb to 2a, and the -12v to 0.3a. Test #2 sees only minor changes on the 12v rail as it is coming in at ~45mV of ripple/noise. However, the 5v rail is coming in at ~30mV of ripple/noise, and the 3.3v rail is peaking at ~55mV of ripple/noise!
120v Input
100v Input
Test #3 is equal to approximately 75% of the rated capacity of N1 750 G5 at 45c. This makes Test #3 equal to 566W 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 ~85mV of ripple/noise while the 5v rail peaks at ~30mV of ripple/noise. The real star of the show is the 3.3v rail which touches ~70mV of ripple/noise!
DC Output Quality Summary
The overall DC Output Quality of the EVGA N1 750 is terrible. The N1 750 ended up posting a peak trace amplitude on the 12v rail of ~85mV followed by ~70mV on the 3.3v rail and ~30mV on the 5v rail during our normal tests. The fact that this unit was this bad and out of specification is not the whole story.
If we look back at this unit, we see that this unit was out of specification as early as Test #2 when the 3.3v rail only had a 5A load on it! Just 5A! That is nowhere near its rated capacity and the 5v/3.3v combined load was were nowhere near their combined capacity. That means that this unit is not even a 375W unit let alone a 750W unit! Terrible! Let’s move on now and see what we can pull from the ashes of this mess (Hint: It is not a Phoenix)!