Seasonic FOCUS Plus 850 Gold 850W (Page 4 of 4) | Reports

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 have to be taken into consideration -- of which certain criteria consists 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're not going to try to BS you 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, it 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, initial consumption was 11.1W as measured by our wall meter -- indicating the basic load-free power consumption of the power supply is excellent. Independent reviews from websites with professional load testing equipment showed the Seasonic FOCUS Plus 850 Gold 850W delivered excellent efficiency, voltage regulation, and ripple across all 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 are within 4%. The PG (Power Good) delay seems to be well within its rated range and general power supply standard at 370ms.

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 (P, measured in watts), reactive power (Q, denoted as VA-R), and total power (S, written as VA). While these components all measure power, they are not the same as each other. What we want is the average usable power, with as little wasted 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 can then be easily calculated by P/S. The ideal value is 1.00, and this is where active PFC comes in. Under nominal loads, the power factor value of the Seasonic FOCUS Plus 850 Gold 850W was at 0.95, indicating that the active PFC function is working well.

This power supply unit comes blessed with the semi-passive fan operation, and for the most part, it definitely stays pretty quiet. Even when the fans are on, according to our APH Networks scale, where 0 is silent and 10 is the loudest, I would rate the FOCUS Plus 850 Gold 850W at 2.5/10 acoustically under nominal loads. I never really found the noise from the power supply to be distracting, and the semi-fanless operation worked as intended.

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

Seasonic may have been targeting the mainstream audience with their FOCUS Plus lineup, but the performance of this power supply allows it to fight alongside the best. According to our affiliates with professional load testing equipment, it delivers excellent output and efficiency. It may have lagged behind their flagship power supply when comparing efficiency, but the Seasonic FOCUS Plus 850 Gold 850W cleared the Gold standard all the time. Combine the performance with a practically quiet Hybrid Mode operation and a lengthy ten-year warranty, and you can already paint the FOCUS Plus 850 Gold a winner. Furthermore, when you factor in the fiercely competitive retail pricing of $110 USD, it is easy to see this is one of the best bang-for-your-buck power supplies you can get.

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