Temperatures, Fan Speed, and Acoustics


The two heatsinks remain at reasonable temperatures throughout testing. We've seen much worse results with other power supplies topping out at up to 90°C, so the worst result of ~54°C on the secondary heatsink is quite good. It reaches this point at about an 80% load, and then the fan speed increases and temperatures remain static up to 110% load. This indicates that everything is working properly and there shouldn't be any problems with long-term use of the power supply, and even if it's running at closer to 100% load.


The fan spins at a relatively slow 860RPM up to a load of 300W, at which point it begins to spin faster. It's at 1100RPM at 80% load (720W), and it no longer qualifies as a quiet PSU. Beyond 80% load, fan speed increases rapidly up to the maximum 2000RPM, keeping things cool as we have seen in the temperature graph, but your ears might not be as happy....


If your goal is to have a quiet or near-silent power supply, you will want to keep this PSU under 500W of load. Once we pass 700W, noise levels increase rapidly from 20dB(A) up to a maximum 31dB(A). Given the relatively tame temperatures, Cooler Master certainly could have lowered fan speeds and noise levels more, as the heat sinks are usually in the 40-50°C range. However, we won't complain too much as it will be quite difficult for most users to come anywhere near 100% load (or even 80% load) on this power supply.

Efficiency and PFC Conclusion
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  • andlcs - Wednesday, July 30, 2008 - link

    Solid polymer capacitors are ELITE brand.
    http://www.chinsan.com/product/index.asp?id=22">http://www.chinsan.com/product/index.asp?id=22
  • sheh - Tuesday, July 29, 2008 - link

    20% load efficiency at is lower than 85% regardless of input voltage.
  • strikeback03 - Tuesday, July 29, 2008 - link

    IIRC they test by the ATX methodology, not the 80Plus loading, which might account for the difference.
  • MrOblivious - Tuesday, July 29, 2008 - link

    Or it could be the unit to unit variation, the different temperature, or the different load pattern, etc. ;)
  • JarredWalton - Tuesday, July 29, 2008 - link

    Definitely true. The 80Plus loading methodology differs from the standard ATX loading, and that can easily account for the 1-2% difference between what Christoph measured and what CM reports.
  • MrOblivious - Tuesday, July 29, 2008 - link

    80Plus does list what the requirements for certification on each test report (115v 60hz) and the load steps used to accomplish them. You can see the UCP report here: http://www.80plus.org/manu/psu/psu_reports/SP215_C...">http://www.80plus.org/manu/psu/psu_repo..._MASTER_...

    They don't list the temperature there but IIRC it is 25c (will have to check when I get home). Also, 80 Plus Silver is 85-88-85% not 82-85-82% as it seems to be indicated.
  • tomoyo - Tuesday, July 29, 2008 - link

    I was just about to mention this as there's some misinformation on 80plus scattered about in the article. Hopefully you'll clean that up soon. To me it's a pretty big achievement to get 85-88-85 at 25C on 115V on a huge 900w psu like this one. One thing I've noticed is that some of the new low power psu models are showing extremely high low wattage efficiency such as 90-92%. Some of these include the two dell 80plus silver models and some of the new actel ones. 80plus Bronze is much easier to achieve as most 80plus psu's are already near 85% in the middle range.
  • JarredWalton - Tuesday, July 29, 2008 - link

    "80Plus Bronze requires at least 82% efficiency at 20% load, 85% efficiency at 50% load, and 82% efficiency at 100% load. 80Plus Silver bumps the requirements up to 85%/88%/85% for the same 20%/50%/100% loads. In short, the Cooler Master 900W UCP had better be able to reach 88% efficiency."

    I'm not sure how that's at all confusing. As to the UCP 900W actually achieving Silver in our tests, it does appear to fall just short at the 20% load mark, but only by ~1% (84% efficiency when it's supposed to be 85%). I'm not going to worry overly much on that point, as there's a certain margin of error in testing.
  • MrOblivious - Tuesday, July 29, 2008 - link

    "Before you get too carried away with the high efficiency, however, we need to rain on your parade a bit. The 80Plus Silver badge means that most users will get at least 82% efficiency, but even 20% load represents a power output of 180W, which for an idle system represents a significant amount of high-end hardware."

    Since that is NOT what 80Plus Silver means it could be a bit misleading.
  • JarredWalton - Tuesday, July 29, 2008 - link

    Ah... I see my typo. I put that paragraph in, and apparently hit a 2 instead of 5. Should be 85% there, you're right....

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