Load 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. 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 starts with our 120v, 100v, Torture, and 80 Plus Tests.

120v and 100v Load Testing Results

GIGABYTE P650B 650W Power Supply 120v and 100v Load Testing

Test #1 is equal to approximately 25% of the rated capacity of the GIGABYTE P650B at 45c. This makes Test #1 equal to 173W 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. The results of Test #1 show the main positive DC output rails starting off above nominal. The efficiency for this unit is starting off in good shape at a value of 85.41% at 120v AC input and 84.58% at 100v AC input. We see the exhaust temperature is 47C at 120v AC input and 48C at 100V AC input.

Test #2 is equal to approximately 50% of the rated capacity of the GIGABYTE P650B at 45c. This makes Test #2 equal to 326W 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. Test #2 sees the DC output voltages decline relative to what we saw with Test #1. The largest changes are 0.04v drop on the 5v rail, up to a 0.04v drop on the 12v rail, and a 0.02v drop on the 3.3v rail. The efficiency has moved up to 86.59% at 120v AC input and up to 85.68% at 100v AC input. We see an exhaust temperature of 50C at 120v AC input and 53C at 100V AC input.

Test #3 is equal to approximately 75% of the rated capacity of GIGABYTE P650B at 45c. This makes Test #3 equal to 486W by loading the 12v rail to 36a, 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 5v rail drop by 0.04v and the 12v rail has dropped by up to 0.04v again. The 3.3v rail drops by 0.03v. The efficiency in Test #3 moves down to 85.39% at 120v AC input and down to 84.06% at 100v AC input. We see an exhaust temperature of 52C at 120v AC input and 55C at 100V AC input.

Test #4 is equal to approximately 100% of the rated capacity of the GIGABYTE P650B at 45c. This makes Test #4 equal to 650W by loading the 12v rail to 50a, the 5v rail to 5a, the 3.3v rail to 3a, the +5vsb to 2a, and the -12v to 0.3a. In the final regular test, we see the 12v rail move down by up to 0.04v. The minor rails also see a small decrease of 0.02v. The efficiency has dropped as we see it come in at 83.11% at 120v AC input and 80.93% at 100v AC input. We see an exhaust temperature of 54C at 120v AC input and 57C at 100V AC input.

Torture Test

GIGABYTE P650B 650W Power Supply Torture Test

The Torture Test is equal to approximately 80% of the rated capacity of the GIGABYTE P650B at 45C. This makes the Torture Test equal to 519W by loading the 12v rail to 38a, 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, the GIGABYTE P650B is still doing decent. The DC output voltages are generally in line with what we have been seeing in the 120v load tests. The efficiency is good, for this class of product, as we see a value of 84.14% and the exhaust temperature is 63C.

80 Plus Load Testing Results

GIGABYTE P650B 650W Power Supply 80 Plus Load Testing

As we see here, the GIGABYTE P650B posts efficiency values of 84.92%-86.49%-82.88% efficient using 80 Plus’ load testing parameters. This puts the unit right in the 80 Plus Bronze standards. However, we do use different equipment than 80 Plus for our testing and there is always a bit of component variation.

Load Testing Summary

The GIGABYTE P650B did a decent/good job for what it is in our initial load testing. When we look at the voltage regulation, we see that the GIGABYTE P650B had peak changes of 0.12v on the 12v rail, 0.1v on the 5v rail, and 0.08v on the 3.3v rail. These absolute values are in the specification and good overall. In relative terms, these results are slightly worse than what we saw from the Seasonic FOCUS GM-650. Overall, that means that this unit is facing some tough competition as it was not doing better than the incumbent top 650W unit we have seen even though its absolute values were good.

When we look at the efficiency values posted today, we see that the GIGABYTE P650B ranged from 83.11% to 86.59% efficient at 120v AC input and 80.93% to 85.68% efficient at 100v AC input. Also, this unit posted values in our 80 Plus Test that were within the 80 Plus Bronze level that it is certified for. Lastly, the exhaust temperature peaked at 54C at 120v AC input, 57C at 100v AC input, and 59C during the Torture Test. These efficiency results are not great in the “Grand Scheme” of things but it is only meant to have this level of performance so that as bad as it looks initially. So, let’s move on to the Transient Load Tests to see what this unit will do there!

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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...

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