Founded over 35 years ago, Seasonic is one of the first PC power supply manufacturers and today their products are held in very high regard amongst PC enthusiasts. Despite their high popularity and recognition that the brand name has, the company is one of the very few that did not diversify towards other segments of the market. Seasonic is solely focused on the design, manufacturing and marketing of quality PC power supply units.

During the past several years, we reviewed several of Seasonic’s PSUs, including their latest 80Plus Gold and 80Plus Platinum series. Today we are having a look at their latest product series, the 80Plus Titanium certified PRIME. Seasonic designed the PRIME PSUs to offer the best possible performance and quality they could while keeping the price tag within reasonable limits. The series consists of five units, one fanless 600W model and four regular units with their maximum rated power output ranging from 650W to 1000W. In this review we are going to test three out of the five units of the series, the 650W, 750W and 850W versions. (It is worth noting that the 600W and 1000W versions not yet available to the North American markets, which is sometimes a limitation in our sampling.)

Model Price
Seasonic PRIME SSR-650TD $170 incl. shipping
Seasonic PRIME SSR-750TD $175 incl. shipping
Seasonic PRIME SSR-850TD $200 incl. shipping

Seasonic PRIME Titanium
Power specifications ( Rated @ 50 °C )
AC INPUT 100 - 240 VAC, 50 - 60 Hz
RAIL +3.3V +5V +12V +5Vsb -12V
650TD 750TD 850TD
MAX OUTPUT 20A 20A 54A 62A 70A 3A 0.3A
100W 648W 744W 840W 15W 3.6W
SSR-750TD: 750W
SSR-850TD: 850W


Packaging and Bundle

Seasonic kept their packaging very simple, elegant and functional. The artwork is limited to basic geometric shapes and metallic colors. Our early samples came with an error on the packaging as well - the PRIME units are covered by a 12-year warranty, not 10 years as indicated on our packaging. The packaging is very sturdy, with thick cardboard walls and polyethylene foam pieces protecting the product inside.

Inside the packaging, we found the necessary AC power cable, four typical 3M mounting screws, a good user’s manual, a few typical cable ties, five high-quality cable straps with the company logo, a metallic case badge, and a sticker. There were no thumbscrews or black screws included.

The PRIME PSUs are fully modular. Every cable, including the 24-pin ATX cable, is detachable from the chassis. With the exception of the 24-pin ATX cable that is enfolded in black nylon sleeving, the rest of the cables are “flat”, ribbon-like. All of the cables have black connectors and wires.

Connector Seasonic SSR-650TD Seasonic SSR-750TD Seasonic SSR-850TD
ATX 24 Pin 1 1 1
EPS 4+4 Pin 2 2 2
EPS 8 Pin - - -
PCI-E 6+2 Pin 4 4 6
PCI-E 8 Pin - - -
SATA 6 10 10
Molex 5 5 5
Floppy 1 1 1
External and Internal Design
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  • emn13 - Saturday, April 8, 2017 - link

    Higher rated PSUs necessarily have reduced low-load efficiency, even PSU's as good as these. So it's highly unlikely the 600W fanless is a 1000W model minus the fan; that would significantly reduce the efficiency at low loads, which, given their aim with these models, I seriously doubt is a tradeoff seasonic would have been willing to make.
  • SkipPerk - Wednesday, May 3, 2017 - link

    Seasonic makes a 500W fanless unit, but it is simply a 1350W unit without the fan and some big heat sinks. Enermax also makes robust fanless units up to 500W, but they are basically the same high-wattage unit with the fan removed and larger heat sinks. You might as well buy a 1200W or 1350W PSU that does not spin up until it hits a certain wattage (usually 300W to 400W).
  • Lolimaster - Friday, April 7, 2017 - link

    Considering they're titanium, most people just use 1 gpu and don't OC their cpu. They should launch more models, like 450-550w with fan.
  • blahsaysblah - Saturday, April 8, 2017 - link

    Not that i wouldnt have minded getting one, but read the wiki on 80 Plus. Gold is plenty fine. Im very happy with my SFX Corsair SF450 PS that has never turned on its fan(GPU is GTX 1060 6GB). Never seemed hot to touch. A good GOLD PS seems to not generate enough waste as heat to matter. Its almost one year since using it in new PC.

    Of course its positioned nicely, big vent up, for convection, per fine print, and its right under a vent, SilverStone SG13B case. One 140mm fan upfront is only system fan. Its does not get noisy level RPMs either. (just get silverstone atx to sfx adapter that is vented, centers PS, dont get corsair one. last i checked a year ago...)
  • blahsaysblah - Saturday, April 8, 2017 - link

    dang, no edit. i want to add, i made my own set of power cables(all) to de-clutter build. so my experience may be slightly different than yours.
  • djscrew - Friday, April 7, 2017 - link

    Oh wow, the reviews are in and our product is exceptional. Now let's see if we can improve these margins! How would we go about that? Let's see... maybe we can find a manufacturer who can do it for less.
  • surt - Sunday, April 9, 2017 - link

    Online reviews are absolutely merciless when manufacturers do this, it has killed the sales of more than one vendor over the years. Remember OCZ?
  • Solidstate89 - Friday, April 7, 2017 - link

    Interesting. Has Seasonic moved away from Sanyo Denki fans? I thought they used them exclusively?
  • FriendlyUser - Friday, April 7, 2017 - link

    Great review as always. Having a good PSU is essential for the longevity of the components. I mean, what's the point of the 16-phase VRM design of your MB if you are feeding it crap power? And how far can you overclock your GPU if your 12V line is full of ripple and noise? The efficiency is the cherry on top.

    Being a very satisfied owner of a Seasonic Platinum 850W, the only reason I'm not buying the Prime is because the Platinum is already extremely good and it's powering my home server 24/7 for years now.
  • Lolimaster - Friday, April 7, 2017 - link

    You should probably change for the 10-20% efficiency, which your server will run at most of the time.

    That's why lower than 600w Titanium PSU's are more important than useless 750-850w where low load efficiency is not as good.

    Looking at the numbers you're getting 90% efficiency at near 35w load on the 650w vs 90% efficiency at 55w on the 850w model.

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