FSP revamped its Dagger Pro line, and the flagship model with 850 W maximum power output fares well enough against the competition. It is one of the strongest SFX PSUs available on the market today, and it is impressive to see such high power output from such a compact platform. Good parts are used internally, but soldering quality could be better. The cooling fan and the few electrolytic caps on the primary and secondary sides are of high quality, and the same goes for the MOSFETs and SBRs. I have to admit I am not a huge fan of the ACRF (Active Clamp Reset Forward) topology—it is not a top performer because it focuses on keeping the production cost low while increasing efficiency. Still, this Dagger Pro unit achieved relatively high overall performance that could be even higher if transient response were better. In general, ACRF designs don't do so well with transient loads, which a PSU will have to deal with 99% of its operating time. On the other hand, the ACRF topology achieves long hold-up times using smaller bulk caps than those typically found in PSUs.

It isn't an affordable product at $210 in the US, also as the Cooler Master V850 SFX can be found for less. FSP should find a way to drop its prices in the US, which is the most important market for any brand. The next competitor for the Dagger Pro 850 is the Corsair SF750 with 100 W less power output but high performance in all areas. Until more brands offer 850 W in this form factor, choices will be limited.