Efficiency and PFC

With the 80Plus Silver badge, we expect very high efficiency results. Just to clarify, an 80Plus certification requires that a power supply reach 80% efficiency at loads from 20% to 100%. 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.




The results meet the 80Plus Silver requirements, actually reaching a maximum of 89% efficiency, but it's important to note that this is only possible on 230VAC. The 80Plus standard doesn't specifically state whether the efficiency should be measured on 230VAC or 115VAC, so we will have to give Cooler Master the benefit of the doubt. 115VAC users "only" get 87% efficiency. [Ed: Boohoo.] Regardless of how you look at it, this is the highest efficiency we have measured in a retail power supply to date.

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 85% efficiency, but even 20% load represents a power output of 180W, which for an idle system represents a significant amount of high-end hardware. Optimal efficiency starts at around 350W, which pretty much means you will need a quad-core system with dual graphics cards as a reasonable minimum (and probably a bit of overclocking) in order to get full efficiency from this sort of power supply. But then you hopefully already realized this when you saw the 900W rating.


Another part of the 80Plus certification is that the power supply needs to reach at least .9 PFC, but it only needs to achieve this at 100% load. Needless to say, that's not a very difficult requirement to meet, and this PSU has a lower PFC than we have seen with most recent power supplies. PFC goes up with lower input voltages, but most power supplies easily break .99 PFC at lower loads with 115VAC. That said, the difference between .98 and .99 PFC obviously isn't very great, so this isn't something that should seriously concern potential buyers. The result could have been better, but it's not something to lose sleep over.

DC Outputs and Quality Temperatures, Fan Speed, and Acoustics
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  • JarredWalton - Tuesday, July 29, 2008 - link

    "We see very little voltage drop on the rails, which is very good. All of the rails are within 2% to 2.5% of regulation, starting slightly higher than the target voltage and dropping slightly below target at higher loads. Ripple on the 12V rails is also exceptionally good, measuring at most 8mV. Lower voltage rails also perform decently, though not quite as good, measuring up to 21mV. The ability of this power supply to deliver the required wattage with little voltage drop even at higher loads leaves us with a good impression."

    Posting a graph that shows ripple isn't really any more informative than what we did right there: up to 8mV ripple on the 12V rails and 21mV on the 3.3V and 5V lines. You might want to read the text a bit more closely before firing off complaints. We state in the conclusion that the PSU has very good ripple results, and I guess that's probably as far as you got? The previous several pages of test results are there for a reason.
  • Amart - Wednesday, July 30, 2008 - link

    A graph educates people, and shows that you've performed the necessary readings to construct it. Ripple/Noise is arguably one of the most important graphs to have on a review.

    Sure, you had 'something' in this review, which is an improvement over the last few months.

  • Christoph Katzer - Tuesday, July 29, 2008 - link

    With 78mV no company in the high-end field would have released the product...
  • mindless1 - Tuesday, July 29, 2008 - link

    Do you have any evidence that 78mV of ripple has caused any problems by itself, isolated as the variable? The powered parts themselves cause more than 78mV of ripple local to them, where it might matter if it ever did - this if you had a hypothetically perfect 0mV ripple PSU.
  • Zak - Tuesday, July 29, 2008 - link

    I found CM products to have competitive prices - but I don't shop for high end stuff - and I've always received their rebates.
  • nycromes - Tuesday, July 29, 2008 - link

    I too have only had good experiences with their products and rebates. I have heard that others have experienced problems with rebates, but I don't usually hear many complaints regarding their products.

    I guess that some people must get a different experience than others, the question is which one of us had the normal experience and which one of us got lucky. Until I have a bad experience, I am sticking with my Coolermaster products.
  • Glenn - Tuesday, July 29, 2008 - link

    You forgot to mention the business model coolermaster has relied on. Sell your product that has a worth of about $25 for retail price of $75 and then offer a $65 rebate that will likely not get paid!

    Then, when the customer has problems with the product, just make the process to repair or replace so difficult, that only the most persistant buyers will percivere the process to get something done!

    Hey, it must be working for them!
  • JEDIYoda - Tuesday, July 29, 2008 - link

    so what does anything you say have to do with this review?
    For that matter can you back up what your claiming with links??
  • Glenn - Tuesday, July 29, 2008 - link

    It has everything to do with any Coolermaster product review! If the company is poor on customer support, then it affects the value equation for prudent buyers. Sorry you don't understand!

    Do some reading-
  • JEDIYoda - Wednesday, July 30, 2008 - link

    I do understand very well! It is you that has a axe to grind against the Coolermaster products.

    The company support and how they handle problems has nothing at all to do with this review of the product!!

    Yoyr bitch is against the compant itself...the 2 are very seperate!!

    As usual a very well done review!!

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