Hot Test Results (~45°C Ambient Temperature)

The SeaSonic Focus GX-850 has its output specified for an ambient temperature of 50°C. Generally, PC power supply units (PSUs) are categorized based on their temperature ratings, with 40°C typically associated with low-end to entry-level mainstream units, and 50°C designated for quality mid-tier to high-performance products. The 50°C rating of the SeaSonic Focus GX-850 is unsurprising considering its target market and class, and a welcome upgrade over the previous Focus Plus series, which was rated at 40°C.

The performance of PC power supply units (PSUs) tends to diminish as the ambient temperature increases, with the extent of the degradation largely influenced by the design and quality of the unit in question. In the case of the SeaSonic Focus GX-850, the energy conversion efficiency experiences a marginal drop of just 0.4%, a figure that stands out favorably, especially for a quality 80Plus Gold unit. This minor decrement is consistent across the entire load spectrum, exhibiting no notable variance even under substantial load conditions. Such outcomes imply that the thermal stress exerted on the active components is remarkably low to mild, showcasing the design robustness of the SeaSonic Focus GX-850.

In contrast to some models, the fan within the SeaSonic Focus GX-850 initiates almost immediately upon powering on when the ambient temperature is high, reflecting a proactive approach to thermal management. The fan's operation progressively escalates, reaching its zenith when the load approximates 80% of the unit's rated capacity. This approach results in audible sound pressure figures even when the PSU is lightly loaded when the ambient temperature is very high, but, on the other hand, the proactive cooling strategy ensures a reliable operational landscape for the PSU.

Cold Test Results (~25°C Ambient Temperature) Power Supply Quality & Conclusion
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  • GeoffreyA - Wednesday, November 29, 2023 - link

    It's beautiful.
  • Techie2 - Wednesday, November 29, 2023 - link

    This is another high quality PSU from Seasonic. They are the gold standard in PC PSUs IMNHO.
  • HaninAT - Wednesday, November 29, 2023 - link

    My only issue is that I just bought their prior generation Focus GX 850... Oh well... I will need the new fangled PCI-EX power lead eventually anyway.
  • Samus - Wednesday, November 29, 2023 - link

    This exact fan failed on my Seasonic Focus GX-700 after 2 years. It started making rattling noises, the shaft inside the hub rounded itself out of the bearing. Replacing it was a pain in the ass because the fan controller is calibrated for a specific amp fan, and if you use one thats rated over or under the stock fan, it will either spin faster or not spin at all, the later of which was my issue because I upgraded the fan to a beefier ball bearing NMB.

    Seasonic should get a clue and use ball bearing fans in PSU's they market as premium and charge top dollar for. A quick google search will reveal I am far from the only one with a Seasonic PSU fan failure, and while its under warranty, you will be without a PSU for 2 weeks during the RMA process as they do not offer advanced RMA, and the process itself is a frustrating social experiment I lost patience with and opted not to go through.
  • sonny73n - Wednesday, November 29, 2023 - link

    I would just replace the fail fan with a case fan and connecti it to the motherboard. The silent/fan-stop feature is unnecessary because one more running fan would not make a different.
  • Samus - Thursday, November 30, 2023 - link

    If you don't have a fan connected to the PSU, the fan controller prevents the PSU from powering on because it thinks the fan is dead. You could put a resistor in to trick it, but then you are faced with a fan that is running independently of the PSU, disregarding its temperature zone. Sure, you could put a fan in that runs at full speed, it would be noisier than necessary. Or you could roll the dice and try running the fan based on case or CPU temperature which would theoretically scale with PSU load, but...all Seasonic needed to do to avoid ALL OF THIS BS is to put a reliable fan in their PSU's.

    I have a 15 year old PC Power & Cooling Silencer 750 that has way beyond 100,000 hours on it. Original fan, still silent.
  • liquid_c - Monday, December 18, 2023 - link

    15 years equals ~129600 hours. You ran over 100.000 hours during this time? 11 and a half years of non-stop running? I find it hard to believe.
  • bernstein - Wednesday, November 29, 2023 - link

    Why do they still make those huge PSUs with those silly huge and ancient atx power plugs?
    I mean all it does is converting to 12V power… the rest is just useless 5v/3v stuff for long obsolete tech like 2.5” hdds…
  • bernstein - Wednesday, November 29, 2023 - link

    Also, who the hell still needs 10 sata, 3 molex & 1 floppy power plugs. Those things are ancient (well 3.5” hdds are still a thing but, still motherboards with more than 4 sata ports are getting rare…
  • evanh - Thursday, November 30, 2023 - link

    Dude, that's why it's modular. And can even cut off what you don't want.

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