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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Death666Angel - Friday, February 24, 2012 - link
Kingwin/Super Flower have 500W, 550W, 600W and Enermax has 500W and 600W as well.ShieTar - Friday, February 24, 2012 - link
Kingwin has a 300W even, and Sama has a 400W. You can always check for Platinum certified supplies directly at the source:http://www.plugloadsolutions.com/80PlusPowerSuppli...
There are 90 Platinum certifications by now.
adece - Friday, February 24, 2012 - link
Antec has its Earth Watts Series which was recently bumped to Platinum efficiency, although this are not modular, not even semi.elian123 - Friday, February 24, 2012 - link
OK, great. Thanks guys, I'd only noticed reviews of the bigger ones up till now.Martin Kaffei - Saturday, February 25, 2012 - link
I'll test the Antec 450W soon.Leyawiin - Friday, February 24, 2012 - link
Just got a gold X-560. I'll never buy another brand now.AnnoyedGrunt - Friday, February 24, 2012 - link
I have an older Seasonic (can't remember which model), but it is an awesome power supply. I live in a heavily wooded area and often on windy days the trees hitting the power lines will cause the lights to flicker, sometimes my monitor to power cycle, but through it all my computer will stay on and working due to the excellent properties of the Seasonic. I, too, will keep buying what I consider to be the best brand in power supplies these days.Good to hear their current products are even better than the older model I use.
-AG
rrohbeck - Sunday, February 26, 2012 - link
Same here. The other day we had a power glitch and the light went out for a fraction of a second. I went over to my big system to see if it would reboot cleanly (it's also a file server) but it was still running. Nice! It uses an X750 Gold.aurareturn - Friday, February 24, 2012 - link
I have had a Corsair HX 520 modular PSU since 2007. It's made by Seasonic. Still running like a champ.Also have another Corsair Seasonic PSU in my new computer. Running for 2 years now. Still great.
piroroadkill - Friday, February 24, 2012 - link
I had an HX520 for so long, that now I gave it to my brother for his system to replace a generic. Still works perfectly.Got myself a Seasonic X-660. The packaging, the look of the thing, the fully modular design - it screams class.