Final Words

The new Focus Gold SGX series marks SeaSonic’s effort to enter the premium SFX PSU market with their own product. SeaSonic’s approach here is refreshingly modest, with the company opting not to build a halo product with a price tag that would instantly drive almost everyone away, but rather to design and develop a very reliable and high-performing PSU with a reasonable $129 price tag.

The high quality of the Focus Gold SGX-650 probably is its biggest selling point. It is an exceptionally well-designed and constructed PSU, with components coming from the best manufacturers and a fantastic assembly job. So it is not surprising that SeaSonic backs their power supply with a 10 year warranty.

Under normal operating conditions we recorded excellent performance figures on all fronts – electrical, thermal, and acoustic. SeaSonic is known for their emphasis on power quality and their new SFX unit is no exception, with exceptional power quality and power stability figures. The operating temperature of the Focus Gold SGX-650 is relatively low and the 120 mm fan is not to blame for that, as it barely is necessary when the unit operates in room temperature and under typical loads.

The Focus Gold SGX-650 also delivers very good performance while operating under high ambient temperatures, but there is a catch – it really doesn't want to be heavily loaded. After all, SeaSonic does de-rate the unit down to 80% capacity when the ambient temperature exceeds 40°C, and in our testing this seems like a prudent move. The overall performance of the power supply drops significantly when it's pushing over 550 Watts while operating under high temperatures, suggesting that these actually are overload conditions for the unit. In fact I'd probably go one step further and suggest that the PSU shouldn't be used with a load over 500 W if it really is going to be used under harsh ambient conditions.

Overall, high performance SFX PSUs are slowly but surely gaining ground on the PC market. And while the current selection of SFX products is rather limited, SeaSonic has certainly created a very interesting competitor with the Focus Gold SGX-650. Thanks to the high quality design of the power supply, it's currently one of the best-performing SFX PSUs available; and that's even if we take into account its disdain for hot environments.

Hot Test Results (~45°C Ambient Temperature)
Comments Locked

38 Comments

View All Comments

  • Mr Perfect - Thursday, March 7, 2019 - link

    Aww, this got my hopes up. The case I have only really works with SFX, not SFX-L and the headline called this a SFX. But hey, at least Seasonic is addressing the SFF market now. For ages they've just ignored the enthusiast SFF segment.
  • abrowne1993 - Thursday, March 7, 2019 - link

    Yep, the included Amazon link even mentions that it's SFX-L in the description. Should really be specified more clearly here.
  • E.Fyll - Thursday, March 7, 2019 - link

    Technically speaking, there is no SFX-L standard; that's just a term made up by SilverStone in 2013 (or 2014, my memory fails me) to describe their SFX units that were longer than 100 mm. I try and only use that term for SilverStone's products as it does not really apply to any other manufacturer (unless they choose to use the term themselves). SeaSonic even specifies that the form factor of the SGX-650 is Intel SFX in the product's manual, which this unit clearly is not fully compliant with. I cannot just baptize it whatever I want myself though, I can only state the facts, as I did on the second page of the review.
  • piroroadkill - Friday, March 8, 2019 - link

    Once enough products fall into a "made-up" standard, it becomes a de-facto standard. That's just how it is.
  • Death666Angel - Friday, March 8, 2019 - link

    That seems like a weird cop-out. All price comparison websites in Germany I know of have SFX-L as a seperate tab and they are not only comprised of Silverstone PSUs. Who do you want to standardize the form factor anyway? As far as I can see, Intel standardized ATX and Via standardized ITX. Are we supposed to just call ITX motherboards not made by Via as "smaller than ATX" motherboards in one paragraph and then just call them ATX in the rest of the review? And of course you can "baptize" the PSU however you want in a review you are writing yourself, just give sufficient explanation and people will more than likely thank you for being more clear than the manufacturer. If you just repeat the manufacturers talking points, reviews are useless. Call a duck a duck and not a somewhat misshapen swan. If someone is first to market with a good idea, they get to name it. If the idea is so good that others start to copy/adopt it, the name likely becomes the standard for the industry.
  • DanNeely - Friday, March 8, 2019 - link

    The thing is that despite Seasonic using the term on their amazon marketing it doesn't quite fit Silverstone's made up SFX-L standard, which is 130x125x63.5. Seasonic made this one 125x125x63.5; which is a hair smaller. Unless bastardized SFX PSUs start to proliferate (like long ATX supplies have) it probably doesn't matter since everything will either be the actual standard and only support 100mm long supplies or support the 130mm length Silverstone's marketing is calling SFX-L
  • E.Fyll - Friday, March 8, 2019 - link

    I believe that using your own example will help you understand why SFX-L is not a real standard.
    For something to classify as a "standard", it first has to have at least some basic specifications published (and adopted by a significant portion of the industry, but even just published would do). When VIA proposed the Mini-ITX standard, they published a lengthy white paper indicating its precise dimensions, expected energy requirements and dissipation, reference guides, etc. On the other hand, "anything longer than 100mm" does not classify as a standard at all and that is why SFX-L has not been adopted as a real standard by the industry. If it eventually will, it will have to clarify precisely how long the product should be.

    And, as I said above, that term was just SilverStone's invention. I cannot pretend to know what their intentions were as a company but the fact is that it never actually was anything more than a marketing term. Besides, you are not calling ATX PSUs that are more than 140 mm "ATX-L", are you?
  • lmcd - Thursday, March 14, 2019 - link

    Why put SFX at all if it's not valid SFX? Why not just put ATX, as it's more compliant with ATX than SFX? There's even an ATX bracket included, so it clearly can be used where an ATX PSU is expected.

    And that's why SFX-L is the correct moniker here.
  • Mr Perfect - Saturday, March 9, 2019 - link

    That's interesting, today I learned that SFX-L isn't a defined standard.
  • Samus - Monday, March 11, 2019 - link

    The irony is the silverstone sfx unit you are mentioning is a 550w standard length SFX PSU, though not modular. Ironic, because this Seasonic - as good as it is, really can’t handle beyond 550w at high temps where the silverstone can.

    The silverstone is $40 less.

Log in

Don't have an account? Sign up now