Hot Test Results (~45°C Ambient Temperature)

During its hot testing phase, the DeepCool PX850G 850W PSU exhibits a significant decrease in efficiency, with figures dropping to 87.9% under a 115 VAC input and 89.5% with a 230 VAC source, compared to 89% and 90.5%, respectively, during cold testing. The drop is substantial but almost equally distributed across the load range, which bodes well for the quality and longevity of the unit. Despite the efficiency reduction in higher ambient conditions, there is no sign of thermal stress at peak loads, even though this unit is rated for operation at an ambient temperature of up to 40 °C.

In hot testing conditions, the fan of the DeepCool PX850G 850W PSU activates at approximately 250 Watts, quickly ramping up to maximum speed as the load approaches 85% capacity. This behavior ensures the PSU remains relatively quiet up to half load but, beyond that point, the noise level significantly increases and makes the unit quite loud. This aggressive fan profile effectively manages heat but results in poor acoustics performance during heavy use.

Obviously due to the overzealous 135 mm fan, the DeepCool PX850G 850W PSU adeptly handles its thermal output, keeping internal temperatures commendably low for its category. During operation with loads exceeding 80% - a range at which the fan runs at its peak speed - the PSU effectively prevents temperatures from even nearing unsafe thresholds, ensuring it remains safely below the limits that would activate the over-temperature protection (OTP) feature or instantly damage any of its components.

Cold Test Results (~25°C Ambient Temperature) Power Supply Quality & Conclusion
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  • GeoffreyA - Tuesday, March 26, 2024 - link

    I haven't tried their power supplies, but the case I'm using is DeepCool's Tesseract. No complaints, and the fans have worked well for five years.
  • Tunnah - Tuesday, March 26, 2024 - link

    "..a significant decrease in efficiency, with figures dropping to 87.9% under a 115 VAC input and 89.5% with a 230 VAC source, compared to 89% and 90.5%, respectively.."

    1.1% and 1% is significant ? Doesn't that boil down to a difference of a few watts ?
  • PeachNCream - Tuesday, March 26, 2024 - link

    When you're writing an article it can be difficult to think about things from an outside perspective. AT has noted via response to comments in the past that there isn't a review like one would find an editor performing before publication so they sometimes rely on readers pointing out things that could be improved and make edits after an article is out the door.

    I can't recall many Anandtech articles that haven't had suggestions from readers in the past probably six or so years. It shows the effectiveness of crowdsourced post-publication review to improve article quality and has been helpful so I believe feedback like yours is always beneficial when there isn't a team of professional writers and editors available.

    And, to be fair, even well-known news sites are in a hurry and cost-sensitive so I see actual paid professional articles with the rare error or typo that slips out before publication. One or two errors per article isn't too bad considering Future doesn't have the same hiring power as an established, well-known company.
  • Samus - Wednesday, March 27, 2024 - link

    Weird comment.
  • Ryan Smith - Tuesday, March 26, 2024 - link

    1% absolute is significant when you're talking about energy losses. Even though this is only a Gold PSU (a couple steps down from ultra-efficient Titanium), that's still an effective increase in energy losses of 10%.

    It's typical and expected for PSUs to lose efficiency in our hot box testing. We've had Gold PSUs fare better than this, though.
  • E.Fyll - Friday, March 29, 2024 - link

    It does. However, that few Watts worth of difference merely due to the elevated temperature, from a technical point of view, is a major concern. The greater the difference, the more the active components are getting thermally stressed. Ideally, a great unit should have a very small difference in performance when the ambient temperature changes by ~20C, as long as the temperature remains under the unit's maximum rating.

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