GIGABYTE P650B 650W Power Supply Review


The GIGABYTE P650B is the second power supply we have seen here at TheFPSReview from GIGABYTE. That first unit, the P750GM, was not a very good product. However, GIGABYTE has been one of the biggest names in the enthusiast community for some time now, even though power supplies have not been their core business or what many users are used to thinking of when they see the GIGABYTE name, so we would hope that they could produce a good unit. So, while our initial hopes were dashed, GIGABYTE does have a large industrial base, so we have hopes for their ability to turn things around today with the P650B. The question is; do our hopes translate into reality this time? Let’s see.

Build Quality

Today’s GIGABYTE P650B starts things off a bit like the P750GM did as the build quality is a bit mixed. The exterior represents a very bland mid-range unit with a little bit of branding. This goes hand in hand with the fact that this unit has not the best cabling (and fixed cabling at that). The integration is generally clean but the PCB is a single-layer affair. The component selection does a bit better than the P750GM did as we do get Japanese capacitors this time via Nippon Chemi-con (wet and solid) and FPCAP (solid). We also get a Yate Loon ball-bearing fan. Lastly, the documentation with this unit is a disaster and the variable 3-year warranty is not making us feel any better about this unit.

Load Testing

Today’s GIGABYTE P650M started off testing in decent to good shape. We saw voltage regulation of up to 0.12v on the 12v rail, 0.1v on the 5v rail, and 0.08v on the 3.3v rail. These numbers would look to be good in a relative sense but, in reality, they are trailing the Seasonic FOCUS GM-650. We also saw efficiency values that ranged from 83.11% to 85.68% efficient at 120v AC input and 80.93% to 85.68% at 100v AC input. These are good for what this unit is, but they are definitely not the best we have seen. When it came to the 80 Plus efficiency numbers, we did see the P650B fall in line with its advertised capability. Lastly, the P650B did pass our Torture Test.

When we look at the Transient Load Tests results for the GIGABYTE P650B, we see that the results are rather decent. When directly loaded, the 12v rail showed a peak change of ~380mV, and the 5v rail had a peak change of ~60mV. During the 12v load, the unloaded 5v rail saw a peak change of ~50mV. In absolute terms, these results are ok and in relative terms, they are mixed with the Seasonic FOCUS GM-650.

DC Output Quality

The DC Output Quality results for the GIGABYTE P650B were bad. To start off, we saw peak ripple/noise values of just ~25mV of ripple/noise on the 12v rail, ~10mV on the 5v rail, and ~10mV on the 3.3v rail during our regular load tests. These values increased to ~50mV on the 12v rail, ~40mV on the 5v rail, and ~35mV on the 3.3v rail. While these values are within specification limits and that means, at a minimum, passing in absolute terms they are not good at all. In relative terms, these results were trailing the Seasonic FOCUS GM-650 by a lot. So, this makes this unit uncompetitive in the current marketplace.


Today’s GIGABYTE P650B is a midrange(ish) capacity unit and it does have a fairly open design. However, the fan it is equipped with is rugged but not generally known for its noise profile. It is also supposed to be efficient (though not as efficient as most these days). So, how does it do in our testing?

Overall, it did ok. Well, it did ok until the end of Test #2 when it was running at 50% load and 100v AC input. At that point, the unit was making enough fan noise to be easily identified in our test environment. On top of that, it developed a very obvious cyclic pattern to its noise output. During our tests below this load/parameter level, however, it was rather unremarkable in our load testing environment. So, it would seem, the unit does ok but not great when it comes to noise output.

Final Points

The GIGABYTE P650B is a passing to ok unit overall. It never really does anything to truly stand out in a positive way and it has real issues. From its somewhat questionable Build Quality to its decent voltage regulation, to its OK Transient Load results, to its terrible DC Output Quality, and its mixed noise output the GIGABYTE P650B is the very definition of a (sour) mixed bag. So, what is this (sour) mixed bag of a unit going to cost us?

Today, we find that the GIGABYTE P650B is currently harder to come by, like all units, and the best price we can find is $66.99 at Amazon. Now, that is a bit lower price than what we have seen from some other 650W units during the pandemic-induced price spikes. However, it seems that this unit definitely needs this lower price point more than most units to make it attractive given how it performs relative to those other units.

Users looking for what might be the best 650W unit on the market will definitely need to look elsewhere or, really, anywhere. However, if you are just looking for a unit that is in this capacity range and will work in a pinch then it might make sense at the right price point. That said, in normal times its current price point is not the right price point. This is very much a barely specification compliant unit and should not be priced anywhere above that position.


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 Power Supply Editor for one of the truly early, groundbreaking, and INDPENDENT PC enthusiast sites ([H]ardOCP) until its mothballing in April of 2019. Paul now brings the same flair and style of his power supply reviews to

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