Internals 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.

External Impressions, Cables, and Connectors Performance Measurements
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  • theeldest - Friday, February 24, 2012 - link

    Maybe it's just me but I didn't see any pictures of the sleeved cables, eventhough they're specifically called out as being quite nice.

    "pics or it didnt happen"
  • Stuka87 - Friday, February 24, 2012 - link

    I was just going to say the same thing. Was looking for photos of the cables but didn't find any.
  • just4U - Friday, February 24, 2012 - link

    I mentioned that earlier.. still waiting for a reply from Martin.
  • Earballs - Saturday, February 25, 2012 - link

    Going based on the picture of the 24pin.. it can't be /that/ nice.
  • cyberguyz - Sunday, February 26, 2012 - link

    All of the cables on my Seasonic Platunum 860 came beautifully sleeved.

    No complaints at all with the quality of this PSU or its bag of goodies.
  • aznofazns - Friday, February 24, 2012 - link

    This might seem really superficial, but the main reason I probably won't get this PSU is because the 24-pin ATX connector on the PSU side isn't compatible with the 24-pin cable on the X-650. When I first heard of the Platinum Series I was intent on getting one due to the longer 8-pin EPS cable (the motherboard tray on my V2120X is too long for my current one to be routed behind). This is important to me because I'm in the process of sleeving all my cables with MDPC-X for the purpose of aesthetics.

    Other than that, this PSU is amazing. Seasonic consistently delivers the very best power supplies in every wattage class, and even their budget offerings outshine the competition. Will the ultra high energy efficiency recover the extra cost over time? Probably not. Almost certainly not. But at least you know you're doing the environment a slight favor and can be quite confident that your components won't be fried by a faulty PSU.
  • rtothedizzy - Friday, February 24, 2012 - link

    If you're happy with the x-650 and you don't need there extra power then there is probably no good reason to upgrade at that cost.

    But.....

    If you're going to all the trouble to individually sleeve the cables then "length of cables" isn't all that compelling of an excuse not to upgrade (if that's you're only reason). It's a very small additional investment in time and $$ to buy a crimper, some new atx pins, and a roll of 18 or 20 gauge wire and make new cables any length you need. It even makes sleeving easier since you don't have to get the sleeve over the connector pin (you can crimp it on after you get the sleeve on the wire). It would also let you get away with 1/16 sleeving instead of the usual 1/8.

    Just a friendly suggestion :)
  • bigboxes - Friday, February 24, 2012 - link

    You do know they sell extraction tools that allow you to remove the connectors so that you can easily sleeve your wiring.
  • rtothedizzy - Friday, February 24, 2012 - link

    Yes. I don't see how you would individually sleeve the cables (as I was talking about) without taking the pins out.

    ATX pins can be very difficult to get dense 1/16 sleeving over, whereas the wire with no pin is not hard at all to get 1/16 sleeving over.

    Or you can just go 1/8 and it doesn't really matter.

    My point remains though, if you're going to individually sleeve your cables then making longer cables out of wires and pins is not much added annoyance.
  • elian123 - Friday, February 24, 2012 - link

    Can we expect platinum PSUs at lower wattages too? Now it only seems 750W and higher?

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