FSP Dagger Pro 850W Report (Page 4 of 4)

Page 4 - Minor Tests and Conclusion

Power supplies are interesting products, because often, reviews of products in this category are conducted and tested in methods that make it difficult to distinguish one power supply from another. Many aspects must be taken into consideration. Certain criteria consist of efficiency, noise, power ripples, and of course the ability to pull out the rated specifications. Because many cannot afford such equipment to obtain results regarding those aspects, articles covering power supplies often come out with less than adequate and acceptable information. As this is a product report -- not a review -- what we are doing is a close examination of the power supply and the internal hardware and build. But what we can do for you is do some minor testing with the results we can present to you with and let other review sites with professional equipment show you the actual test results. We are not going to try to create useless test results by installing the power supply into the latest gaming rig and try to take readings from that, as this is not even remotely the correct way to test power supply units. We understand that many websites do that as a means of load testing, but the results, even if you use an oscilloscope and multimeter at each output location, is not sufficient, nor does it accurately reflect the performance of the power supply.


Using our power supply tester which exerts minimal load on the power supply, the initial consumption was 8.1W as measured by our wall meter unit, indicating the basic load-free power consumption of the power supply was very good. Independent reviews from other websites with professional load testing equipment have shown fairly decent efficiency and voltage ripple control, with some ripple on the voltage rails. This is an 80 Plus Gold certified power supply unit.

Voltages with minimal load are generally accurate, which is a basic requirement of power supplies out of the box. In this situation, all were all within 3%. The PG or Power Good delay came in at 120ms, which follows the latest ATX specification. For reference, the design specifications are supposed to be between 100ms and 500ms. However, 250ms maximum is needed for Non-Alternative Sleep Mode and 150ms maximum for Alternative Sleep Mode.

Active power correction is important to correct AC load line loss. In AC power, there are three components to it, as there is a phase difference between current and voltage. This makes up the power triangle, which consists of the following: Average usable power, or active power (P, measured in watts), reactive power (Q, denoted as VA-R), and total apparent power (S, written as VA). While they all have the same physical units, it is not the same thing as aforementioned. Reactive power actually plays an important role in large power systems for keeping the voltage stable. If there is an insufficient amount of reactive power being injected into an electrical bus, the voltage will become unstable and unable to supply active power to the desired loads. At the distribution level though, reactive power is essentially wasted power, since it does not do any work. Thus, what we want in the case of our power supply unit is active power with as little reactive power as possible. The total power provided over the AC line is the magnitude of the two combined (sqrt(P^2+Q^2)). Power factor is easily calculated by P divided by S. The ideal value is 1.00, and this is where active PFC comes in. The FSP Dagger Pro 850W has an APFC circuit, and the power factor should approach 0.99 under a nominal load.

It is also important to note that this fan will not spin if the load is light, making it completely silent at times. Under regular loads up to 50%, the Dagger Pro 850W is low noise. When the fan does start spinning, I found it to be decent, even when it ramps up. On a scale from 0 to 10 where 0 is silent and 10 is New Year's countdown at Times Square, I would rate the FSP Dagger Pro 850W at 2.5/10 acoustically under nominal loads. This does get louder as the load increases but this is to be expected since the Dagger Pro 850W uses a ball-bearing fan, which is generally noisier. If you are a silent PC enthusiast, the FSP Dagger Pro 850W is a good choice thanks to FSP's great fan curve profile.

FSP provided this product to APH Networks for the purpose of evaluation.

The FSP Dagger Pro 850W is a solid power supply unit. As an SFX supply, It is physically very small, which is great if you want to start an ITX build. Reviews from independent websites indicate the FSP Dagger Pro 850W has decent efficiency and voltage regulation. The ripple control is not fantastic by any means, but is also not terrible and still falls within limits. If you choose to stick to a standard ATX build though, FSP has got you covered with an ATX bracket. You will find a solid selection of internal components built by FSP itself. All the capacitors are Japanese-made, which is preferable for power supply units. Flip the power switch on and you got a reliable ball-bearing fan for cooling the supply. The Dagger Pro 850W also operates semi-fanless, so you can expect no noise from the supply if you are doing minor tasks like internet browsing. The 10-year warranty is also a great addition, being longer than your average PSU coverage. The retail price of $210 is not cheap by any means. With all things considered though, from the size compatibility to the solid internal build and lengthy warranty, I think this is acceptable for a solidly built 80 Plus Gold certified fully modular SFX PSU.


Page Index
1. Introduction, Packaging, Specifications
2. Physical Look - Outside
3. Physical Look - Inside
4. Minor Tests and Conclusion