FSP SFX PRO 450W Power Supply Review

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The FSP SFX PRO 450W is the second SFX power supply we have seen here at TheFPSReview from FSP. However, we have seen a fair number of SFX/SFX-L units from SilverStone as well. The two defining differences are those units were larger in capacity and higher-end units (both the previous FSP unit and the SilverStone units we have seen). So we are left with a bit of an interesting pickle today. Entry-level products in enthusiast’s eyes are a tough balance to strike, to begin with, but then FSP has tied one hand behind their back by making this an SFX unit. So, has FSP come out swinging? Or sucking wind? Let’s see.

Build Quality

Today’s FSP SFX PRO 450W starts things off with a build quality that is not exactly dated but is not as high-end as other SFX units we have seen. This is probably more appropriate for its market position than if this unit was priced any higher than it is or slotted in any higher in the product stack than it is. The exterior gives us a decent enough package that does not over or underwhelms. The unit has fixed cables with a mix of the flat FlexForce style and standard wire loom.

The integration is generally clean on the interior though a bit less cramped on the single layer PCB than we would have expected from an SFX unit. The component selection features Nippon Chemic-con standard capacitors, Teapo solid capacitors, and Apaq solid capacitors. The other big component we see is the Protechnic rifle bearing fan that is better than a sleeve bearing option. The documentation with this unit is terrible and the unit has a 3-year warranty.

Load Testing

The FSP SFX PRO 450W started off testing in “ok” shape. We saw voltage regulation of up to 0.15v on the 12v rail, 0.07v on the 5v rail, and 0.07v on the 3.3v rail. This sounds better than ok, however, the unit’s initial set point was rather low so these values look worse when viewed as absolute voltages rather than a change in voltage. In addition to that, we saw efficiency values that ranged from 83.23% to 85.59% at 120v AC input and 81.82% to 84.29% at 100v AC input. These numbers are not great these days, but the unit did hit its claimed 80 Plus Bronze efficiency across the board. Even though this unit is an entry-level product, this kind of efficiency is starting to pass by even these units these days.

When we look at the Transient Load Tests results for the SFX PRO 450W, we see that the results are hard to judge and easier to just shield the eyes from. When directly loaded, the 12v rail showed a peak change of ~540mV, and the 5v rail had a peak change of ~40mV. During the 12v load, the unloaded 5v rail saw a peak change of ~40mV. In absolute terms, these results are in the specification for their change and the 5v numbers are excellent.

However, due to the low 12v set point, this unit did drop below the ATX12v specification lower limit of 11.4v during this testing. On top of that, these 12v values were much worse than what we saw from the Corsair CV450 (though that unit was not an SFX unit). Now, that said, this is an entry-level offering and it is just a 450W unit. So, these Transient Loads are nothing to sneeze at when it comes to how much of this unit’s capacity they represent when triggered.

DC Output Quality

The DC Output Quality results for the SFX PRO 450W are, again, a bit mixed. During testing, we saw peak ripple/noise values of just ~50mV of ripple/noise on the 12v rail, ~25mV on the 5v rail, and ~20mV on the 3.3v rail during our regular load tests. So, in absolute terms, these values are within specification limits. In relative terms, these results are generally better than the Corsair CV450 even though two of our rails are hitting, or hovering near, 1/2 of the ATX12v/EPS specification limits.


Today’s FSP SFX PRO 450W is a small capacity unit in a small form factor with only middling efficiency. On the plus side it does have a rifle bearing fan which is not the best option, but better than what you get in a lot of lower-end units. So, how did things go?

Things went better than I expected, though the unit did seem to try to bake itself to death a few times to achieve that. It was not until the 75% and up load tests that it was apparent that the unit was adding noise to our load testing environment. Even then, the noise was a low-frequency one, so it was not annoying to my ear in that aspect. Additionally, because this is an SFX unit, it was exhausting right where I sit to take measurements rather than away. The caveat to all of this, of course, is that, normally, you don’t point a power supply exhaust at your face. So, the noise that you perceive will be lower than what I got with this unit today.

Final Points

The FSP SFX PRO 450W is a borderline unit in the entry-level SFX marketplace (which is a product segment I don’t imagine is very large, BTW). The SFX PRO 450W gave us decent build quality, passing voltage regulation, passing DC Output Quality, and……….uh…..numbers in the Transient Load tests. Certainly, there is a bit of caveat on the Transient Load Tests there given the unit’s performance, but it is largely going to be unit to unit variable based on what the 12v set point is from the factory. So, that said, what is the unit going to cost us?

Today, we find that the best in-stock price is $74.99 at Amazon which makes this unit one of the cheapest SFX power supplies from a recognized brand you can buy. The form factor and compact size are also appealing for anyone that needs a small power supply. At $74.99 we are starting to move in a direction price-wise than a few dollars more will start getting you more modern topologies and, quite frankly, better units. For instance, the Corsair SF450 can often be had for just $20 more.

The entry-level market is always a tough one because the performance is never stellar and the price point makes or breaks you. If this unit has a MIR on it at the time of purchase, or a temporary price drop, then it becomes a much more attractive option. At $74.99 right now there are a few too many question marks (including would this performance be repeated on other units given what we saw with the Transient Load Tests) to say jump on this unit today.


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 The FPS Review.

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