Seasonic Platinum Series 860W - Platinum without the Fuss
by Martin Kaffei on February 24, 2012 12:00 AM ESTInternals and Electronics
As our research has shown the Platinum 860W is very close to the 80 Plus Gold X-1000 and X-1250. This is not surprising, since the earlier model PSUs already had a considerably higher efficiency than the requirements for 80 Plus Gold certification. Seasonic employs a full-bridge resonant converter that utilizes the transformer in full. You don't need any diodes for commutation during turn-off. As a result this circuit design is predestined for higher power ratings.
The current and voltage pulses of the resonant circuit run nearly sinusoidal and the transistors turn on at zero voltage. Together with the low resistance on the drain-source path the power dissipation is much lower during turn-on, turn-off, and the saturation of those transistors. Accordingly the heatsinks are much smaller now. However, differences between the larger models are the "weaker" MOSFETs and the missing third primary capacitor (which you can see a silkscreened space for in the above image).
There are some minor changes from the previous X-series. One of them is connected with the resonant circuit itself. Two conductions of the IC CM6901 (on a small PCB) lead to a small inductor, which is located between the resonant capacitor, the resonant coil, and the small "auxiliary coil" to relieve the main transformer. With this the current is measured in the resonant circuit to improve regulation. A second winding is connected to the main PCB and the magnetic flux in the core passes through the regulation winding.
We found out that there are two +12V sources at the transformer with two large ground planes. The PS232F offers over current protection for +3.3V, +5V and +12V (up to four outputs). This is the second sign that this PSU has multiple +12V outputs. The pins for the over current measurements are connected to +12V without exception. Seasonic does not officially favor a single output, but many ODM customers such as Corsair do, which might be the reason for the "single rail" rating on their label. Nevertheless it is basically a multiple 12V rail design.
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Martin Kaffei - Friday, February 24, 2012 - link
Tcha, that's one disadvantage of those full modular PSUs.I always forget the cables. I'm sorry.
Cobra Commander - Friday, February 24, 2012 - link
Displeased with the subjective noise levels - they're 100% meaningless to me.Create a standard on how Anandtech wishes to objectively-benchmark PSU noise and stick to it, please.
Oxford Guy - Saturday, February 25, 2012 - link
Agreed.The chart says "strong fan noise" and then the article's body text talks about how very quiet it is at high load.
? ? ?
vicbee - Friday, February 24, 2012 - link
What?!? They didn't get your Platinum Award?!? how disappointing...rtothedizzy - Friday, February 24, 2012 - link
I think you might have overstated your conclusion a bit.While this is a great power supply it's hard to argue that it is superior to its 1000W big brother which (I believe) matches this one in all the efficiency, regulation, and noise benchmarks and adds another 140W.
The only way I can see you claiming this one is better is maybe a price/W metric or whenever you wrote this article you weren't aware of the 1000W version.
just4U - Friday, February 24, 2012 - link
Martin,How about some pictures of the cables please. These things are important to many of us as we like to see what they look like for case work arounds asthetics, what type of ribbons their using or sleeving etc.
TY!
Martin Kaffei - Saturday, February 25, 2012 - link
Done.There will be more pictures next week. The 24-pin cable is probably a bad example, but this was the only picture I made. The peripheral cables are more opaque.
tzhu07 - Friday, February 24, 2012 - link
I'm currently on a SeaSonic X750. I like the hybrid fan mode. Keeps things quiet when I'm not doing much.Nfarce - Friday, February 24, 2012 - link
I've got a SS 620W Bronze running an older now-backup gaming rig and it's been flawless for over two years (overclocked E8400, SLI'd o/c GTX 275s). However, the reviews of the 1000W version of this PS on NewEgg are a little disconcerting with a 25% failure/DOA rate - especially at this level of supposed quality (and price).AssBall - Friday, February 24, 2012 - link
$220... ouch. But I guess if you need the best, you pay for it.