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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marraco - Sunday, February 26, 2012 - link
"The Best PSU Ever" cannot have a noisy fan.cyberguyz - Sunday, February 26, 2012 - link
"The direct competitors include the already mentioned Enermax Platimax 750W / Platimax 850W and the Golden King Platinum design (Kingwin LZP-750) from Super Flower. The latter offering isn't just questionable in name, but the missing overcurrent protection and MOV are also a major drawback. As such, we wouldn't put that particular unit in the same category as the Seasonic; Super Flower products in general use cheaper quality."It was a reasonably good article tarnished by the reviewer's obvious hate for anything not Seasonic.
There is no taking away from Seasonic at putting out a kickass power supply. I like them so much I bought one myself and it is currently powering the system I am writing this on. But to unilaterally state something like "Super Flower products in general use cheaper quality." without posting quantitative data to back it up or "The latter offering isn't just questionable in name, but the missing overcurrent protection and MOV are also a major drawback" without actually looking at the reasons why they are not included (and there is one if you bother to look). Are these actually required on a power supply with a single large 12v rail (OCP is definitely a must for mutiple 12v rails to keep a power hog on one of them from burning out the limited rail)? For what? Please expand on why this is such a major drawback?
kensiko - Sunday, February 26, 2012 - link
Well said.It's not because Super flower produced cheaper power supplies that all their power supplies are cheap.
I hope Martin will think before making another statement as that.
Risforrocket - Monday, February 27, 2012 - link
Heck yeah I already bought one. So glad this review shows it to be as good as I thought it was going to be. All my power supplies have been Seasonic in recent years.cyberguyz - Tuesday, February 28, 2012 - link
It is an excellent PSU. I replaced a Corsair HX850 with it (the Corsair was losing some of its regulation edge with age). So far I am really happy with its clean power delivery, tight regulation and efficiency (I hate waste).The downside is that it is a costly beastie but that is to be expected. It is after all one of the best available (yes there are others just as good) in that wattage range. Quality costs.
While I would not call this review objective, the product itself does merit some of the author's excitement. I would look to jonnyguru.com for more technical and objective power supply reviews though.
Cheers folks!
LintMan - Tuesday, February 28, 2012 - link
It looks like Seasonic finally increased the length of the ATX12V/EPS12V cables a bit - but they're still too short!For many/most case and motherboard layouts these days, those cables need to be able to reach from the bottom-mounted PSU around behind the MB, up to the very top edge of the MB. Even in some mid-size cases, 65cm isn't long enough! My Seasonic X750 had 55cm cables and I had to buy a 15cm extension for it with my Antec P280 case, and even then it was barely long enough. These cables really should be 75cm to cover most non-jumbo cases.
shawkie - Sunday, May 13, 2012 - link
Technically I'm talking about the 1kW version (SS-1000XP) and can't comment on the 860W version but it seems that the fanless mode is a complete lie. My PC has an i7 3770T (45W TDP) plus an SSD and an optical drive. I haven't measured it yet but even under full load I doubt it hits 100W. And yet its now idling in 22 degC ambient and the PSU fan is spinning. Its definitely in Hybrid mode and if I flip the switch it gets louder. Its really, really quiet but all the specifications say it should be "fanless" and "0 rpm" up to 30% load. If I'd known that wasn't true I would have got the 460W fanless instead.owen10578 - Sunday, December 18, 2016 - link
Im way late to the party but can anyone answer which connectors are connected to which 12v rails? Because I think my unit keeps on tripping if I load the CPU and GPU and the OCN guys said I might be plugging all my components to all one 12v rail.owen10578 - Sunday, December 18, 2016 - link
Im way late to the party but can anyone answer which connectors are connected to which 12v rails? Because I think my unit keeps on tripping if I load the CPU and GPU and the OCN guys said I might be plugging all my components to all one 12v rail.