The BitFenix Formula Gold 550W is the first BitFenix power supply we have seen here at TheFPSReview. However, BitFenix has been around for a while now and they have been a growing brand. One of the real issues this unit may face today is that this unit is a smaller capacity and more entry-level product. In this market, pricing is brutal and people often have outsized expectations for the unit they are seeing when they look at this segment. So, the biggest question today will be; can BitFenix make everyone happy and price this unit right? Let’s see.

Build Quality

Today’s BitFenix Formula Gold 550W starts things off with a build quality that is very good to excellent (especially when we consider the market segment this unit lives in). The overall build quality does just about everything right from exterior design to the interior component selection to the integration and soldering quality. The component selection is a prime example of excellent quality as it features Nippon Chemi-con and Rubycon standard electrolytics paired with FPCAP solid capacitors. So, while sparse looking, the Formula Gold 550W seems to hit all of the points needed to make a good unit. This is all coupled with a manual that is not so great and a 5-year warranty.

Load Testing

Today’s BitFenix Formula Gold 550W provides us with passing results. We saw voltage regulation of up to 0.2v on the 12v rails, 0.17v on the 5v rail, and 0.18v on the 3.3v rail. In addition to that, we saw efficiency that ranged from 87.30% to 91.11% efficient at 120v AC input, 84.03% to 90.22% efficient at 100v AC input, and 88.09%-91.04%-87.32% in the 80 Plus tests. By themselves, these efficiency numbers would be very good/excellent, but the voltage regulation was only passing. While this unit is passing, it is hardly inspiring us given the absolute specification limits and there are likely a number of better 550W units on the market in this segment.

When we look at the Transient Load Tests results for the BitFenix Formula Gold 550W today, we see that these results are very good/excellent which stands in a bit of opposition to what we saw with our regular load tests. When directly loaded, the 12v rail showed a peak change of ~280mV and the 5v rail had a peak change of ~65mV. During the 12v load, the unloaded 5v rail saw a peak change of ~60mV. In absolute terms, these results are excellent and in relative terms they are as well as this unit is just 550W in capacity! Therefore, this unit has stepped things up a notch here compared to what we generally see and compared to how it was doing earlier.

DC Output Quality

The DC Output Quality results for the BitFenix Formula Gold 550W were passing which is good but not great. We saw peak values of ~30mV on the 12v rails followed by ~25mV on the 5v rail and ~20mV on the 3.3v rail. These values are within specification limits but, even by absolute terms, they are not excellent as this unit was pushing ½ of the ATX12v specification limits with the minor rails. In relative terms, the 12v rails did better but that can only make up for so much. So, overall, this unit is once more passing but not impressing in this test.


Today’s BitFenix Formula Gold 550W is small capacity unit with a rifle bearing fan that has high efficiency levels, an open design, and advertising that says it will be a quiet unit. For quiet cooling enthusiasts, the stars seem to be aligning. How this all worked out in our load tests was not far off from this prediction. Until the full load tests this unit was undetectable in our load testing environment. During our full load tests, however, the unit was apparent and was contributing to the overall noise profile. This is kind of interesting as normally we would say it is unlikely for users to hit full load with a power supply when we are looking at 1000W or 850W units. But, today, we are looking at a 550W unit which is much easier to hit full capacity on. The only major limiting factor to doing this is the lack of PCIe connectors on this unit which make drawing a 550W load on this unit somewhat harder. So, this unit seems to be very nicely behaved and should be a very good option for most users, but this is partially because it is somewhat artificially limited in its ability to be loaded.

Final Points

The BitFenix Formula Gold 550W is a passing power supply today. The Formula Gold 550W gave us excellent build quality, passing voltage regulation, passing DC Output Quality, and very good/excellent Transient Load results while also being very quiet. As you see, this is a bit of a mixed bag. However, that is somewhat expected for more entry-level products as you can’t get everything for a low low price. That said, how low is that low price?

Today, we find that the Formula Gold 550W can be had for around $69.99. That is a bit of a weird price point for this unit as the units above it in price are better units. The units below it in price are not that much, or at all, worse units which make for a tough sell. Perhaps the most notable feature of this unit that might give it a reason to be purchased is going to be its noise output level. However, most lower capacity units in low powered builds are going to be “quiet enough”. For real quiet cooling enthusiasts perhaps that isn’t the case and that fact would dictate this units main target demographic it seems. If you want small capacity, and just about as quiet as possible, then the Formula Gold 550W is an excellent choice. If you want most other characteristics, you will likely be able to find a better fit with other options.



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...