OCC ATX Power Supply Testing Methodologypaulktreg - June 11, 2008
Category: Power Supplies
OCC Power Supply Testing Methodology:
The main aim of any review must be to give the reader an unbiased opinion on whether the power supply is fit for purpose, of sufficient quality to recommend its use and provide information, which will assist the reader in making his/her decision on which power supply to buy.
I have over the past few weeks, looked at tons of power supply reviews on the internet, and some, but by no means all, leave at lot to be desired. Indeed there are many excellent reviews out there with power supplies tested to a standard that I cannot hope to attain at the present time, but these are in the minority. It is not good enough to simply hook a power supply to a computer, run a few programs, measure the voltages with a digital voltmeter (or even worse use bios voltage monitoring) and reach a valid conclusion. Reviews based on this form of testing tend to spend more time on how “nice” the power supply looks and include photographs from every conceivable angle. This method of testing power supplies proves nothing and will lead the author to unknowingly recommend power supplies that just shouldn't be used in certain configurations or perhaps shouldn't be used at all. A substantial number of readers will be involved with overclocking in one form or another and for that they require a stable high quality power supply. I am of the opinion that the power supply is an important part of any system and not enough thought is given in its selection. I will spend less time on how “nice” a power supply looks and more time on how it actually performs.
The only way to test a power supply is to load it up to its maximum quoted output power, sustain it and take accurate measurements of voltage and current to verify correct operation. I will try and take the power supply up to its maximum in three, maybe four steps. The power supply may very well fail before the maximum load is attained and in this case, there is no point in increasing the load, as things are downhill from here. Input and output power measurements are needed to check efficiency and this requires some form of power meter on the AC input and measurements of current and voltage on the outputs. It is also important to know the quality of the supply and this requires the use of an oscilloscope to monitor the ripple and noise levels.
I have neither the specialised test equipment nor financial resources needed to analyse a power supply to what is considered industry standards. However, the series of tests I do perform are comprehensive enough, in my opinion, to reach a valid conclusion. The benchmark for all my testing will be the Intel ATX12V V2.2 standard.
My power supply reviews will follow the standard OCC format for power supplies, until we reach the testing stage and on the next two pages, I have tried to explain the changes and give a brief overview of how I will perform the tests.