FSP DAGGER PRO 550W SFX Power Supply Review

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Build Quality

As we already know the FSP DAGGER PRO 550W features a 92mm overhead fan design. Normally, quiet power supplies utilize 120mm or larger overhead fans due to the ability to move a larger volume of air at slower speeds than a smaller diameter fan. However, the FSP DAGGER PRO 550W is an SFX form factor unit that restricts the size of the fan that can be used. The key criteria in our evaluation, however, is whether or not the cooling solution is sufficient, not necessary its sound level or form factor.

External Build Quality

The external build of the FSP DAGGER PRO 550W differs from what we see from a lot of power supplies due to its size as an SFX form factor unit. However, among SFX units it is very similar to the recent FSP SFX PRO 450W. So, it conforms to much of what has become standard among enthusiast power supplies over the last 10 years or so (the layout is standard for a single overhead fan design with APFC and fixed cables) except for size and it is very similar to the much earlier FSP Dagger 600W we reviewed. The finish we see today is a slightly textured black, that should be durable, and the unit carries the FSP DAGGER PRO branding. The branding is, however, applied via stickers.

The FSP DAGGER PRO 550W comes in at a total length of ~4 inches while the cables come in at a length of ~12″ to 20″ to the first or only connector. Additionally, the cables are all FlexForce style cables.

Internal Build Quality

Once we open the top of the FSP DAGGER PRO 550W, we see a very compact unit that is much different than the recent SFX PRO 450W in layout. The topology is similar to that unit, though, as we again have an ACRF primary and a secondary with synchronous rectification paired with DC-DC VRMs for the minor rails. The heatsink layout is very sparse with what appears to be just two thin heatsinks installed today. The fan coupled with these heatsinks is a dual ball bearing Power Logic fan rated at 0.55A at 12v. When we look at the back of the PCB, we see the 12v MOSFETs here using the housing as an additional heatsink. The soldering on this dual-layer PCB is very well done.

On the primary side, the DAGGER PRO 550W input filtering begins on a PCB attached to the housing itself with some Y capacitors, X capacitors, and a coil. The filtering then trails onto the main PCB. The bridge rectifier is on an add-in PCB stuck between two coils and it lacks a heatsink. As we move around to the primary side proper, we find the main input capacitor which is provided by Nippon Chemi-con and rated at 420v 330uF 105C. This is followed by a coil and then the APFC power components on a heatsink to the interior. The main switching transistors have their own small heatsink

The secondary side of this unit is rather crowded today. In this area, we find the main transformer and, of course, the DC-DC VRMs. These VRMs are housed on their own PCB and we see a solid Teapo capacitor populating this PCB. The fan controller is also on the DC-DC VRM PCB which is interesting. Additionally, there are a few Rubycon and Nippon Chemi-con capacitors scattered throughout the secondary in various places and roles. The modular PCB itself is next and it is well constructed and populated by yet more Teapo solid capacitors.

Build Quality Summary

Today’s FSP DAGGER PRO 550W is the third SFX power supply we have seen here at TheFPSReview from FSP. The exterior of this unit is probably as well built as the FSP Dagger 600W we saw originally. Some of the actual branding approaches are a bit lower down the quality scale than we might think of when we see the PRO moniker though. When we move to the interior build quality, we see a modern design that is executed with an eye towards the cost. This is apparent when we see the ACRF topology.

Otherwise, the integration is well done for such a small form factor. When it comes to the component selection we see Nippon Chemi-con and Rubycon standard capacitors along with Teapo solid capacitors. The fan is a dual-ball-bearing Power Logic unit that has its pluses and minuses but there certainly worse options out there. So, let’s move on now to the load tests and see how this unit does there!

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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