Seasonic M12D 850W: DC-to-DC Perfection?
by Christoph Katzer on November 26, 2008 12:00 AM EST- Posted in
- Cases/Cooling/PSUs
Introduction
We visited many power supply companies during the past year, and many of them have commented, "the power supply market is dead -- there's nothing new that can be done to attract more customers." That's not entirely wrong, as PSUs are one of the components most people only think about when their old unit fails, or when building a new system. However, it's still important for power supply companies to research new technologies and features, especially if they want to stand out from the crowd. The most recent feature to make its way onto the scene is DC-to-DC technology, with several companies now sporting high-end PSUs that use it. For example, we have the previously tested Enermax Revolution 85+, Silverstone's Zeus 1200W, and Antec's Signature Series.
DC-to-DC technology is nothing revolutionary, as power supplies have always had 3.3V and 5V rails; the difference is simply that instead of taking these directly from the transformer, these rails now split off from the 12V rail -- hence, DC-to-DC. Like other companies, Seasonic has worked on implementing this technology, but they didn't want to rush the new products to market. According to Seasonic representatives, they didn't want to have end-users beta testing the technology, instead waiting until their new PSUs were truly ready for public consumption.
Today we are looking at the long anticipated M12D series, which of course features DC-to-DC technology. We want to see if there's actually difference between Seasonic's offering and the other power supplies that use this tech. Enermax already showed us that they can reach 90% efficiency with a DC-to-DC PSU, so we want to see if Seasonic can match that achievement. There's also more to building a quality power supply than raw efficiency of course, as we discussed recently, but it is worth mentioning that Seasonic has achieved 80 Plus Silver certification.
The outward appearance of the new M12D series doesn't break new ground, with Seasonic once again using their standard black design. The casing is 160 mm long, which is slightly longer than usual, but Seasonic has built PSUs for other companies that use a longer casing (i.e. PC Power & Cooling Silencer 750 Quad). Besides the DC-to-DC technology, Seasonic includes a few other interesting features, including a custom Sanyo Denki fan. The PSUs are also supposed to have very tight voltage regulation and use only Japanese manufactured capacitors. The M12D series starts at 750W and 850W, which is definitely at the high end of what most users need. We know in the past Seasonic has tended to focus on more reasonable wattages, so hopefully we will see some of the wattage models in the future.
We are testing the 850W model today, which comes with two 12V rails each rated at 40A. Again, this isn't remarkably different from other Seasonic PSUs, but it does give users plenty of juice on each rail even with sudden large peak loads. The 3.3V rail is rated at 24A and 5V rail is 30A, both of which are fine for modern systems.
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sprockkets - Wednesday, November 26, 2008 - link
Very bad waveform with very high frequency components? The "waveform" exists since it cannot perfectly make a flat line voltage.Besides, the ATX12V 2.3 spec allows 120 mV ripple for all 12V lines and 50 mV ripple for the 3.3 and 5V lines. It is very well within spec, and consider that these ripple specs are stricter than previous versions of the ATX12V spec, you are going to be fine.
valdir - Wednesday, November 26, 2008 - link
Waveform exists since we are looking and measuring it... and there are good and bad ripple and noise waveforms on the DC rails, just compare with Antec Signature or Corsair 750W or Enermax Revolution or... definitively a very bad waveform.These waveforms are more like very high frequency noise covering ripple and this is not good, since on the PSU's DC rails we should see ripple and not the same noise level.
mindless1 - Saturday, November 29, 2008 - link
Actually it won't make a bit of difference in use. The day a little bit of ripple or it's frequency matters, will be the day we all start using linear PSU again.fri2219 - Wednesday, November 26, 2008 - link
Why does Seasonic insist on putting crappy ADDA fans in 150.00+ units? For the same price, they could at least source from Panasonic or Yate Loon.That ticking sound in the "heavily undervoltaged fan" (nice heavily murderaged of the englished language, there) is incredibly annoying for those of us who haven't destroyed our hearing by playing our iPods at 90db every day for the last 5 years.
mindless1 - Saturday, November 29, 2008 - link
WTF? Yate Loon is the bottom of the barrel, ADDA is mid quality. If you want a yate loon on your case wall it's not so bad but those fail pretty frequently when placed horizontally in a PSU.sprockkets - Wednesday, November 26, 2008 - link
Perhaps you can re-read page 1 where it says it uses a Sanyo Denki fan.And, what is "murderaged" spelling hypocrite?
Slash3 - Wednesday, November 26, 2008 - link
Wooshed.JarredWalton - Wednesday, November 26, 2008 - link
FWIW, that was another error with the speech-recognition. Dragon NaturallySpeaking does so well that sometimes I miss errors in dictation. Apparently, it thinks "undervoltage" is an allowable word, but I know I said "undervolted". Whatever.In case you're wondering, Christoph is not a native English speaker, but he is fluent in at least English, French, and Chinese -- besides his native tongue of German. Feel free to critique his use of a second tongue; me, I'm happy to speak English, Danish, and some German. Anyway, I do pretty heavy editing of his text to clean up the English, but errors slip through on occasion. I was pressed for time on this one (had to run off to the airport) so I didn't give the final text a second proofread.
RallyMaster - Wednesday, November 26, 2008 - link
"That's not entirely wrong, as PSUs are one of the components most people only think about when their old unit sales, or when building a new system."What does "old unit sales" even mean? Are you sure you're not saying "old unit fails?"
Spoelie - Wednesday, November 26, 2008 - link
Page 1"The PSUs are also supposed to have very tight voltage regulation in the future only Japanese manufactured capacitors."
I'm not quite sure what to make of that sentence.