AnandTech Power Supply Test Methodology
by Christoph Katzer on July 12, 2007 12:00 AM EST- Posted in
- Cases/Cooling/PSUs
AnandTech Power Supply Test Methodology
The only way to test a power supply correctly is with special equipment designed for such tests. This starts with programmable loads, which allow the loading of precise amperages on the power supply. Next, a power meter will be needed to measure the exact amount of power used during testing. Power meters can be found in a variety of versions already, ranging from the simple to the complex, and it's good to see that some publications already test with this method.
To test the quality of the DC output we need an oscilloscope as well. This is important since each output has certain ripple and noise levels, and these are different with each power supply - even those from the same manufacturer. The ripple and noise are leftovers from the electric pulse, and every power supply should implement certain measures to reduce the ripple to an acceptable grade. The actual Power Supply Design Guide specifies that each +12V rail should not have any ripple over 120mV and the +3.3V and +5V rails should not have any ripple over ~50mV. Unfortunately we cannot present these tests right away since we are still working on the best methods. We will conduct those measurements soon and include them in the reviews.
It should be quite clear now that we will need some serious equipment to conduct all these tests. To assure our readers of the most professional and accurate reviews on the web, we are building our PSU test lab based on equipment from the renowned company Chroma. With the Chroma test equipment we can make clear and very accurate measurements and load power supplies controlled in ways that are impossible to achieve using only a PC. On the following pages we will introduce our equipment and the ways they will contribute to future power supply reviews.
The only way to test a power supply correctly is with special equipment designed for such tests. This starts with programmable loads, which allow the loading of precise amperages on the power supply. Next, a power meter will be needed to measure the exact amount of power used during testing. Power meters can be found in a variety of versions already, ranging from the simple to the complex, and it's good to see that some publications already test with this method.
To test the quality of the DC output we need an oscilloscope as well. This is important since each output has certain ripple and noise levels, and these are different with each power supply - even those from the same manufacturer. The ripple and noise are leftovers from the electric pulse, and every power supply should implement certain measures to reduce the ripple to an acceptable grade. The actual Power Supply Design Guide specifies that each +12V rail should not have any ripple over 120mV and the +3.3V and +5V rails should not have any ripple over ~50mV. Unfortunately we cannot present these tests right away since we are still working on the best methods. We will conduct those measurements soon and include them in the reviews.
It should be quite clear now that we will need some serious equipment to conduct all these tests. To assure our readers of the most professional and accurate reviews on the web, we are building our PSU test lab based on equipment from the renowned company Chroma. With the Chroma test equipment we can make clear and very accurate measurements and load power supplies controlled in ways that are impossible to achieve using only a PC. On the following pages we will introduce our equipment and the ways they will contribute to future power supply reviews.
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Adul - Thursday, July 12, 2007 - link
I'd love to see a power supply catch fire :). Maybe one of the cheaper ones will break enough for this.CrystalBay - Thursday, July 12, 2007 - link
I would also like to see a short video of substandard PSU's lighting up...I'm sure many enthusiasts have had Dram's start flaming or smoke. But I have never had a PSU actually catch flame out....
Martimus - Thursday, July 12, 2007 - link
I had a Antec NeoPower PSU spew black smoke. It was not fun. Also fried my motherboard. It was less than 6 months old too, and I wasn't using it at anywhere near it's supposed capacity.BladeVenom - Thursday, July 12, 2007 - link
Then test power supplies that are in the range that most people actually need. Also test some budget ones. Let's see which ones are good for the money, and which ones are fire hazards.
xsilver - Thursday, July 12, 2007 - link
what is meant is that the idea of having a psu is NOT to load it to 100% capacity.and the problem being that it is very difficult to get a stable and repeatable psu testing setup.
I highly recommend that industrial manufacturers be pointed out just like in xbit labs reviews. That way we will know that antec has 3 or more suppliers providing psu's and be able to tell the seasonics from the other crud ;)
Wesleyrpg - Thursday, July 12, 2007 - link
hmm i wonder if thats why some people rave about Antec and some people like me curse them! I'd have to say Antec have the worst failure rate by far, probably at about 75% in the first year, where i can buy a $22 550W Generic (Honli) and only have about a 25% failure rate, maybe thats related to the power supplys released into australia by antec.imaheadcase - Thursday, July 12, 2007 - link
I kid! :Pgersson - Thursday, July 12, 2007 - link
just a red 'X'gersson - Thursday, July 12, 2007 - link
nevermind -- working already :-)