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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  • Jammrock - Friday, April 7, 2017 - link

    I've had the 650W version since Oct 2016. It's powering an i7-6700K with a GTX 1080. Absolutely zero issues so far. It's quiet and efficient and solid. Can't recommend it enough. If the price tag fits within budget....

    My only gripe is the motherboard power cable. It's a split cable and kind of annoying to deal with. But then you only need to mess with it once per motherboard upgrade so really it's a very minor issue.
  • close - Friday, April 7, 2017 - link

    Just out of curiosity, why didn't you go for the 750W if the price difference is just $5? Is it for efficiency reasons (less efficient than the 650W at your system's typical load)?
  • Bullwinkle J Moose - Friday, April 7, 2017 - link

    Low load efficiency was the reason I purchased a 350 Watt Seasonic SSR-350ST from newegg a few days ago instead of the SS-520GB or the SS-620GB @ B&H Photo for the same price when they were on sale last week

    I wish you would cover power supply replacements for Monitors sometime

    Had a standard 19 Volt LG power supply crap out last month and the only replacements I could find are basically CRAP

    A T-Power replacement actually MELTED within 3 days and became non-functional before it had a chance to burn the house down

    Other online stores for Monitor power supplies are complete scams selling more Chinese CRAP instead of the original equipment listed in their ads

    I ended up using a VERY Old 120 Watt - 15 Volt Athena Laptop power supply with the T-Power Plug spliced to it's output

    It works fine on 19 Volt LG's and cost about $30 around 10 years ago

    I was a bit worried about EBay replacements for LG supplies but may need to try that route next time unless anyone knows where to buy "QUALITY" supplies with output current rated "above" what the stock LG's put out

    Computer Power supplies are well covered at all the tech sites...
    Monitor Supplies are never covered
    Why is that?
  • Bullwinkle J Moose - Friday, April 7, 2017 - link

    Modular cable outputs for 2 or 3 computer monitors on the back of these computer power supplies would be nice!

    I'd buy THAT!

  • alin - Friday, April 7, 2017 - link

    Most laptop psu's are 18-20v. Plenty of them around :)
  • Grimmm - Friday, April 7, 2017 - link

    When I was overclocking a Korean IPS I bought a high power brick designed for medical applications on an online industrial parts catalog. Cost a bit, but works perfectly (after swapping the output connector)
  • Jammrock - Tuesday, April 11, 2017 - link

    @close - Two reasons. 1) At the time the 750W was more than a $5 difference. I purchased mine >6 months ago. 2) I try to size my PSUs to the load so they hit the peak of efficiency for the majority of my tasks. Granted, the difference is minimal for this particular 80Plus Titanium PSU, but old habits die hard.
  • Sparkyman215 - Friday, April 7, 2017 - link

    Wow. I've read a lot of your psu reviews, and I don't think you've used the words 'insanely good', 'unbelievable' - and of course 'mythical'. Even though the price is high, getting one of these and keeping it through upgrades for over a decade is probably a better deal than a lower end psu you have to replace several times
  • blahsaysblah - Friday, April 7, 2017 - link

    It's pretty disheartening to think that they wont be modernizing either the cable layout/connectors or any other aspect of the PSU. It would be great if they could make things smaller/more direct. With the move to a single 12v rail, you would think they would move to single hot/ground per CPU/GPU connector. They have changed the insides a bit. Why there isnt some sort of data/status connector between PSU and MB... At very least to communicate PSU temps, but to add voltage,.. info, instead of all those sense cables.
  • JasperJanssen - Saturday, April 8, 2017 - link

    Moving to single wire bundles wouldn't gain you anything, and in fact loses you things. The reason there's 2 or 3 wires in those pcie bundles is current capability -- both for the connector and for the wires. So you still need the same amopunt of copper (actually, slightly more) to do that, if you move to having single wires instead of doubled. but those wires are going to be stiffer and more expensive. In other words, that's a bad idea.

    And re Status connectors -- while Seasonic could unilaterally add something custom, how many motherboard companies do you think would put a matching connector on? Also, the only thing that even *can* be monitored inside a PSU is the fan speed. That's why they occasionally had a fan speed wire coming out, which you can put on a motherboard fan connector. Only nobody ever used that function.

    There just isn't any digital logic inside a PSU to communicate with. Motherboards can monitor voltages just fine on their own through the ATX connector.

    (also, changing the connector type requires changing both the power supply *and* the GPU, which is awful.)

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