Our load tests utilize a couple of FAST ATE active load testers and a variety of other equipment such as an oscilloscope, power conditioner, temperature probe and a power consumption meter. You can read more about our standard testing approach here.
The tests performed are based around six conceivable setups that are out there and progressively load down the PSU up to the power supply's limits or 1000W, whichever comes first. Since our test equipment's limits are greater than that of the Mushkin Enhanced Joule 800W, we can test it to the maximum.
Running the Mushkin Enhanced Joule 800W power supply through our tests revealed some surprising numbers. Starting with the voltages, we see some readings on the 12V rail that are a tad higher than most power supplies we have reviewed lately, but are still well within specifications. As the loads increase, voltages drop across the board as you would expect, but there are no drastic drops and the readings on all of the rails are well within specifications and look good from start to finish.
Perhaps the area where the Joule 800W excelled at the most was in the ripple department. Start out during the first test, ripple was almost non-existent at only 5mV peak to peak. As the loads increased, so did the ripple, but it was very marginal from test to test. During the final test, ripple crept up to a maximum of 22mV under full load.
As the Joule 800W power supply is rated for 80Plus Silver efficiency, we should expect to see efficiency numbers at or above 85%, 89%, and 85% at 20%, 50%, and 100% loads respectively. The numbers for the Joule 800W are right where they should be at their respective loads and while we don't have a test at exactly 50%, the unit shows no signs that it isn't capable of reaching its rated efficiency.
Normally, you don't expect anything spectacular from a budget power supply and usually have to worry about at least one test coming close to failing. The Mushkin Enhanced Joule 800W performed flawlessly with plenty of room to spare in every test from start to finish. It offers a very fair selection of cables and connectors for an 800W power supply that should complement just about any system the power supply is capable of pushing and does so at a very attractive price of $110.
The unit isn't without its discrepancies, however, and that is often the price that you pay for a budget power supply. The biggest complaint is lack of a lengthy warranty for your power supply. While almost every manufacturer of power supplies has switched to a "standard" minimum of a five year warranty, Mushkin only offers a two year warranty for the Joule. You also have the primary capacitors that are rated for 85C instead of the more favored 105C capacitors. While they didn't give us any problems during testing, a year or so of use and degradation of the capacitors could prove this to be the weak point in the power supply.