Seasonic S12II: 330W to 500W of Silence

Conclusion

Anyone who has read about Seasonic on the Internet has almost certainly seen comments about their good quality, high efficiency, and extremely quiet designs. After testing two of the latest models we can definitely validate these comments. The S12II is one of the best power supply series on the market, sufficient for all but the most demanding systems. By looking at the lowest and highest rated models, we wanted to show the full range of what Seasonic offers with their new S12II series.

While there are many similarities between the two units, however, they still cater to different market needs. The small version is very attractive for users looking at mATX or HTPC computers for the living room where silence is the primary concern and a large power draw often isn't necessary. The 500W model can serve that market as well, but it can also support a decent high-end system and is only limited by the two PEG connectors it offers. As long as you don't need to run HD 2900 XT CrossFire or 8800 GTX SLI, there is very likely a Seasonic S12II that can fit your needs.

Efficiency Comparison


In the efficiency comparison we show the highest measured result of each tested unit. Both the largest and smallest Seasonic S12II power supplies score an 85% efficiency rating using a 230VAC input. For the most common loads, regardless of input voltage efficiency should still stay above 80%.

The DC outputs were good and stable, and we found very little to complain about with either unit. The cables of both units are of reasonable length with up to 80cm of the 500W version. The 330W version has slightly shorter cables and offers a wide range of connectors with a maximum length of 65cm. given that it's highly doubtful anyone would be looking to place the 330W version into a big tower, the length of the cables is not a problem; in fact, for use in small boxes and HTPC systems the shorter cable lengths are even preferred. The 330W version offers a single 6-pin PEG connector capable of handling anything up to a moderate high-end GPU. The bigger version has two 6-pin PEG connectors, one of which can also function as an 8-pin PEG connector. This is sufficient for powering more moderate SLI/CrossFire configurations, or for running a single top-end graphics card.

Anyone searching for a very silent power supply with good quality and performance will find the S12II series very attractive. They have delivered the lowest noise levels out of any power supplies we've tested so far, with the 500 model reaching a maximum noise level of only 28dB(A) -- practically silent, even in a worst-case scenario. Keep in mind that this kind of low noise is only possible through the use of a very slow turning fan. In the test we measured up to 1350 RPM with the 330W version and up to 1850 RPM on the 500W model. Slow turning fans do not move much air through the power supply, and that means in a poorly designed power supply you would get incredibly high temperatures and likely high failure rates. However, this doesn't apply with the S12II since the heatsinks stay relatively cool and Seasonic uses high-end components rated for up to 105°C. Having high-efficiency certainly helps.

Finally, let's take a look at the prices, and unfortunately this is the one area that will cause many users to think twice. Seasonic power supplies are definitely not cheap, especially considering the power ratings. The S12II 500W sells for around $110, and while we couldn't find the S12II 330W (we could only locate the older S12 330W), the S12II 380W starts at around $63 -- plus shipping, of course. Prices are similar in Europe, and in Germany we found prices of €82 ($114) and €46 ($64), excluding the shipping. Users will need to give careful thought to whether or not the features and performance offered can justify the price. For users looking to build a really silent system, the answer is a resounding yes. Even if silence isn't your primary concern, however, Seasonic's power supplies are definitely worth your money.