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Corsair answers questions on recent product issues

by Scott Bicheno on 10 July 2009, 10:26

Tags: Corsair

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PSU reclassification

[HEXUS] Okay, on to the 80Plus Gold versus Silver PSU questions.  What is the difference between 80Plus Silver and Gold?

[Jim] About 2% [laughing].  Seriously, the difference is 2% in efficiency.  80Plus Silver means that your PSU delivers 85% efficiency at a 20% and 100% load and 87% at a 50% load.  80Plus Gold sets those targets at 87% efficiency for 20% and 100% loads and 90% for a 50% load.  Man, that's a lot of percentages!  If you're as confused as I was trying to spit that out, visit and check out the details.


[HEXUS] Why did your PSU get wrongly certified?

[Jim]  I'm not sure I would characterize it as "wrongly" certified.  According to the 80Plus organization, the unit we sent in for certification is an 80Plus Gold PSU.  We have every legal right to claim 80Plus Gold.   However, the unit we sent in to them showed lower results on our test equipment.  It was very close to reaching Gold but didn't quite make it on the 100% load test.

We have elected to certify the PSU as 80Plus Silver because that is exactly what we designed it to be: the very best 80Plus Silver PSU on the market.  The fact that a single unit passed 80Plus Gold doesn't mean we can guarantee that every customer would get a PSU that met that standard.

There are so many factors that go into the efficiency rating: production variances, component variances, differences in test rigs, temperature differences on the tested units, and so on.  Across the bell curve of units we product, some will be at the very high end of the efficiency spectrum, some right on our targets, and some at the lower end.  The middle of that distribution curve is what the majority of our customers will get, in terms of the efficiency of the PSU they buy.  We know that we can guarantee 80Plus Silver across the full curve because that's exactly what we designed the PSU to deliver.

The fact that we're so close to 80Plus Gold is a testament to the quality of the design.  The fact that we won't certify as 80Plus Gold is simply that we can't guarantee every unit produced would have the favourable variance that would cross that threshold from Gold to Silver.  Keep in mind that we cleared 80Plus Gold by less than half a percent!

Of course, in fairness, I'd like to point out that no one has passed 80Plus Gold with much more.  In fact, all of the 80Plus Gold certified supplies have passed with less than 1% to spare on one or more measures and one is "certified" with just 0.01% (one one-hundredths of one percent!) to spare.


[HEXUS] What obstacles are you finding to getting it re-classified?

[Jim] I don't think it is fair to say there are obstacles.  We've asked the 80Plus group to allow us to use the 80Plus Silver logo and they've granted us permission to do that (though I have to say, I think they think we're crazy!).  We'd like to have it moved into the 80Plus Silver category as well, and will work with them to get that done.