Seasonic S12D 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, is not nearly 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 9W as measured by our wall meter unit -- indicating that the basic load-free power consumption of the power supply is practically some of the best we've seen so far. The lowest we've seen is the Seasonic M12II 500W at 8W, but that's a lower wattage power supply. For reference, however, the Cooler Master Silent Pro M 1000W that recently passed by APH Networks also has a minimum power draw of 8W. Independent reviews from websites with professional load testing equipment showed that the Seasonic S12D series power supplies delivered excellent efficiency, voltage regulation, and ripple across the board -- right up to its rated wattage.

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 0.2V. The PG (Power Good) delay seems to be well within its rated range and general power supply standard at 300ms.

A nominal load of 120W on the Seasonic S12D 850W had the power factor 0.95 -- optimistically, 0.98-0.99 is the best, but it gets closer to optimal as the load increases to its designed capacity.

As we had always expected from Seasonic power supplies, the S12D 850W is a very quiet power supply -- under regular load, the power supply is almost inaudible; all you would hear is a silent hum of the San Ace fan motor. That's only if you listen very carefully. While this is very subjective, I am quite a picky person on noise and the loudest component in my entire system is my hard disk. On a scale from 0-10 where 0 is silent and 10 is the loudest, I would rate the Seasonic S12D 850W to be at 1.5/10 under nominal loads. There's turbulence noise only when the fan spins up to a somewhat high RPM when the power supply is past 50% to 60% load. As the load increases, the S12D will increase voltage to the fan -- in which the higher the load, the more audible the fan is. Under our nominal load of around 180W to 220W this power supply is very quiet, and most computers in the idling state should be around this range. However, once you push it to over 50%-60% of its maximum capacity, the fan will start to kick in like all power supplies. Most people won't have a computer that uses that much power anyways, especially in idle conditions. Overall, in terms of noise, the Seasonic S12D 850W won't disappoint.

Special thanks to Zoe over at Seasonic for making this report possible.

The Seasonic S12D 850W continues the general excellence of Seasonic power supplies. Unsurpassed quality, practically overbuilt internals, high reliability, excellent performance, and low noise emissions are all admirable traits of the Seasonic S12D 850W. At approximately $120 USD at press time, it's a high power Seasonic that has surprisingly competitive pricing!

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