Seasonic M12D 850W: DC-to-DC Perfection?
by Christoph Katzer on November 26, 2008 12:00 AM EST- Posted in
- Cases/Cooling/PSUs
Efficiency and PFC
We measured up to 89% efficiency using 230VAC, which is near the top of our efficiency charts. A few power supplies have managed 90% efficiency, but as we mentioned elsewhere a difference of 1% isn't very significant. Looking at lower input voltages, efficiency is still good but the curves aren't quite as nice, with 120VAC reaching 88% efficiency, but only for a very small range of loading. After reaching the peak efficiency, the curve on 120VAC drops pretty quickly.
The M12D doesn't support 90VAC, which is listed on a sticker next to the AC input. Normally we don't have any problems testing with 90VAC, but this particular power supply definitely doesn't work properly; voltages went up and down like a roller coaster, so we used 100VAC instead of the regular 90 for the above charts. At 100VAC, the efficiency curve looks even worse, reaching a peak value of 86% at 200W and then immediately dropping. Running a load of just 200W on an 850W power supply definitely wouldn't be the best use of your money, so if you need a lower input voltage we would look elsewhere.
Getting back to where this power supply really performs well, 230VAC delivers great results. Even with just 10% load (85W) the M12D still manages 85% efficiency, which is a fantastic result. In Europe, you can run everything from 80W up to nearly 900W and still stay above 85% efficiency. 120VAC is decent as well, staying above 83% efficiency from 80W up to 800W.
We have seen much better PFC results in other power supplies; particularly under 230VAC, this unit doesn't perform that well. It reaches a maximum of .98 -- still good, but not what most people would expect from a high-end unit. PFC with other input voltages is also lower than what we normally see.
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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.