450w-500w PSU Battle Royal

You guys asked, "What about regular mid-range PSUs?" So we bought five power supplies and then tested them to see if they would do what they were advertised to do. A melting fiery mess proves you get what you pay for. 5 PSU enter, 1 PSU leave.

continued...

Ripple and Regulation Testing

Since voltage output is not the only concern when it comes to quality DC output we next examined the ripple and regulation characteristics of the Powertek 500w. We examine these points since unnecessary ripple can cause premature failure of sensitive components in a number of different PC subsystems.

The DC output quality was logged via our digital oscilloscope and the EasyScope II software package. Each divider horizontally represents 2ms while each divider vertically represents 0.05v or 50mv. The ATX specification states that a unit should remain at or below 120mV of ripple and noise on the 12v rail while under 50mV on the 3.3v/5v rails.

Control Test Graphing

Article Image

This image is the blank background control test on an unused connector from our SM-8800 during the Powertek 500w testing. This lets us determine what the background noise looks like during testing. If at anytime a trace deviates from this reading that is the noise/ripple being logged by the oscilloscope for that rail. As you can see the trace is flat and shows as a blue line obscuring the axis. If during a test the axis becomes visible but a waveform is hard to discern it is most likely due to the amplitude of the trace being small in relation to our voltage divider.

120v and 100v Input

Article Image Article Image

Test #1 is equal to approximately 25% of the rated capacity of the Powertek 500w at 45c. This makes Test #1 equal to 130w by loading the 12v rail to 8a, the 5v rail to 2a, the 3.3v rail to 3a, the +5vsb to 2a, and the -12v to 0.5a. The results of Test #1 are very bad. With only a 130w load the Powertek's 5v rail is already beyond the 50mV allowance under the ATX12v specification at both 120v and 100v. The remaining rails are all very active as well with the 3.3v being the closest to the limitations imposed by the ATX12v specifications.

Article Image

Test #2 is equal to approximately 50% of the rated capacity of the Powertek 500w at 45c. This makes Test #2 equal to 264w by loading the 12v to 17a, the 5v rail to 9a, the 3.3v rail to 8a, the +5vsb to 2a, and the -12v to 0.5a. Test #2 at 120v showed massive increases in the amplitude of the traces on all rails, most obviously the 12v. The 5v rail was already out of specification and now the 12v rail has joined it with only a 264w load. The units failed so quickly in Test #2 that no data was logged for the 100v testing.

The DC output quality results were much like the load testing results, very bad. At a mere 130w load the Powertek 500w was out of specification on the 5v rail. Then as soon as the load was increased to 264w from 130w the 12v rail also went out of specification. This is the absolute worst DC output quality encountered to date in our power supply reviews, and is most likely damaging overtime to components receiving power from this unit. I don't think it can be said enough but this power supply is bad, very very bad.