Hot Test Results (~45°C Ambient)

For the testing of PSUs, we are using high precision electronic loads with a maximum power draw of 2700 Watts, a Rigol DS5042M  40 MHz oscilloscope, an Extech 380803 power analyzer, two high precision UNI-T UT-325 digital thermometers, an Extech HD600 SPL meter, a self-designed hotbox and various other bits and parts. For a thorough explanation of our testing methodology and more details on our equipment, please refer to our How We Test PSUs - 2014 Pipeline post.

The SX1000 is designed to deliver its advertised performance with an ambient temperature of up to 40°C, a bit cooler than our standard 45°C hotbox. Although the unit did operate inside the hotbox without significant issues and did not shut down even at maximum load, there were significant signs of thermal stress. Naturally, the energy conversion efficiency takes a hit, dropping an average of almost 1% across the load range. The drop, however, is not equally distributed, as the SX1000 is almost just as efficient as it was outside the hotbox until the load reaches 40%, then the efficiency degrades as the load increases, and the efficiency drop is almost 1.7% at maximum load. This suggests that the components are getting significantly thermally stressed – which is to be expected, looking at the internal temperatures of the unit.

Rarely ever we see temperatures greater than 100 °C inside a PSU, either because their cooling is sufficient or because their thermal protection circuitry will shut them down. Neither was true for the SX1000, as the temperature did surpass 100 °C under maximum load with the unit operating inside our hotbox. Still, the SX1000 stayed in operation and performed within the expected parameters, even though it was clearly on the verge of shutting down due to thermal overload.

Even though we would expect the fan of the SX1000 to start almost immediately inside our hotbox, it actually did not. The thermal circuitry started the fan when the load reached 100 Watts, meaning that the SΧ1000 should stay dead silent with the PC idling even inside a very hot enclosure. Still, once the load increases even slightly above that point, the fan will start and its speed will start increasing sharply, as the SX1000 is trying to cope with the thermal load in these adverse conditions. It reaches its maximum speed when the load is just 400 Watts, with the sound pressure levels being very high at this point. With the fan unable to do anything more for the cooling needs of the SX1000, the internal temperatures reach uncomfortably high levels when the PSU is heavily loaded under such operating conditions.

Cold Test Results (~25°C Ambient) Power Supply Quality & Conclusion
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  • CheapSushi - Thursday, July 29, 2021 - link

    I wish tech sites and people would stop talking about SFX as if it shouldn't just be the standard PSU already. SFX and SFX-L should be every new modern PSU. 1000W shouldn't be surprising. It should be "why do you need 1000w SFX PSU". It should just be the norm of what to expect options wise. Why do we still want huge massive bricks? The entire industry is improving. It's like ignoring M.2 form factor because 3.5" HDDs exist. Why do you need a smaller had drive? See, sounds ridiculous. The same could be said about laptop chargers. They're finally getting smaller on average. Why can't we embrace SFX and SfXL as the norm. The more that is made, the cheaper it gets. The level evens out on price parity with legacy sizes. There are case adapters too. It just makes a huge amount of sense. Even in a big case, you still save volume. I'm using SFX in a Rosewill 4U for example. The adapter from Silverstone gives it more air vents in the same space. It's great. It's nothing unusual. Plus another thing with higher watts is it's the only way to get more SATA power ports. Reply
  • whaletail - Sunday, August 1, 2021 - link

    Considering this is the first 1000W SFX-L PSU to market, doesn't seem like the market's ready for an SFX/SFX-L norm yet. As more consumers/enthusiasts demand smaller PSUs, which doesn't seem far-fetched, more momentum will develop in that direction, but we're not there yet. Reply
  • Oxford Guy - Wednesday, August 11, 2021 - link

    ‘doesn't seem like the market's ready for an SFX/SFX-L norm yet’

    Umm... what reality is ready for is wattage that conforms to the laws of physics in a practical manner.
    Reply
  • Oxford Guy - Wednesday, August 11, 2021 - link

    That said... better heatsinks may have helped. Better efficiency (‘titanium’). A better fan.

    Most importantly, though... not using power pigs like Rocket Lake and thus having no need to try to stuff 1000 watts into a small form factor.
    Reply
  • easysteelchina - Friday, August 13, 2021 - link

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  • besterino - Tuesday, August 24, 2021 - link

    This is the only SFX PSU actually able to power a (read: one) 3090 GPU.

    A couple of months ago I built a watercooled 5800X+3090FE system in a DAN A4 case (wiith external radiators, will not discuss "y tho?") and the Silverstone SX800-LTI PSU shut down consistently in various games, if I did not limit the power limit on the 3090 to ~80%. When I put this 1000W PSU in, all problems gone.
    Reply

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