Seasonic SSR-650PX PSU Review: High Performance Without Breaking The Bank

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Final Analysis

Seasonic's Focus platforms are among the most popular around because they offer a solid list of capabilities for the price you pay. The SSR-650PX costs about $110, yet serves up tight load regulation, good ripple suppression, and of course high efficiency since it is 80 PLUS Platinum-certified.

The only weakness we identified was the minor rails' transient response, which lags the competition's performance. Those rails are referred to as minor for a reason: they aren't heavily used any more. Still, for as long as they're part of a power supply's specifications, we expect them to perform optimally. Apparently, more capacitance is needed in the corresponding regulation circuits to achieve smaller deviations during transient loads, increasing production cost. Of course, there is no perfect product. Although the SSR-650PX fares really well right out of the box, it'd be even better with a bit of tuning on the minor rails.

This is a highly capable PSU able to power potent gaming and video editing workstations. That's one reason we'd like to see Seasonic include a second EPS connector, which would make the SSR-650PX compatible with motherboards built for AMD's Threadripper CPUs. Currently, there are very few 650W PSUs with two EPS connectors (Aerocool's Project 7 650W and be quiet!'s Dark Power Pro 11 650W are two examples), and those cost more than Seasonic's offering. Nonetheless, we think high-efficiency models in this capacity range should be ready to support enthusiast-oriented platforms. Under normal (not overclocked) conditions, a solid 650W PSU can accommodate two fast graphics cards without a problem. So why limit the PSU's compatibility with a  single EPS connector? On the other hand, you could argue that Seasonic's SSR-750PX sells for just $10 more, includes the two EPS cables we're asking for, and offers 100W-higher capacity.

There is no doubt that the 650W Focus Plus Platinum serves up significant value. This PSU is one of the best options in its capacity class. You only need to look elsewhere if the SSR-650PX's noise is an issue. Corsair's RM650x is one option, though it's less efficient, as is the Aerocool Project 7 650W, which costs more and can be difficult to find.

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Disclaimer: Aris Mpitziopoulos is Tom's Hardware's PSU reviewer. He is also the Chief Testing Engineer of Cybenetics, and developed the Cybenetics certification methodologies apart from his role on Tom's Hardware. Neither Tom's Hardware nor its parent company, Future PLC, are financially involved with Cybenetics. Aris does not perform the actual certifications for Cybenetics.

Contributing Editor

Aris Mpitziopoulos is a Contributing Editor at Tom's Hardware US, covering PSUs.

  • DookieDraws
    I won't put anything in my builds, or builds I do for others, other than a Seasonic PSU. Used them for years and have never had any issues. Not saying there isn't any other reliable brands out there, as I know there are, but I'm sticking with what has worked for me.
  • mlee 2500
    What a Coincidence! I bought this very same Seasonic 650PX Power Supply and just last night finally took it out of the box to prep for my new build...and here I find a review for it!!

    The author makes an excellent point that a 2nd modular EPS cable really should be standard these days. With motherboards now supporting USB 3.1, integrated WiFi, a whole slew of 2A fan/pump connectors and tons of other power-drawing features which hardly even existed a decade ago, a second EPS is quickly becoming the norm rather then the exception.

    In my case, with the very popular ASrock Taichi Z series motherboards which requires three connectors (1x24, 1x8, 1x4), I need to obtain a second additional 8pin to 2x4 modular cable. I just happened to contact Seasonic about that not an hour before seeing this review and learned that is their approved distributor and that such a cable costs about $5.00

    If you do need to buy an additional EPS cable, BE SURE TO GET THE ONE WITH THE INLINE CAPACITOR, for the newer SSR series!!

    It was interesting to learn from this article that providing a second EPS cable isn't really typical for most vendors 650W power supplies, which makes me feel better about being in that predicament with Seasonic. I was initially a bit disappointed, but then I've never had a Desktop mobo which required so many connectors before.

    All that being said this appears to be an outstanding power supply, a great value, and given that my previous modular Seasonic Power Supply is still running great after more then 6 years, I remain a Seasonic customer until proven I shouldn't be.
  • Aris_Mp
    I am insisting for quite some time for a second EPS connectors in high-end PSUs and your post clearly shows why. Thank you!