Conclusive thoughts

So what have we learned here today? Well, much more than with the usual power supply tests we hope. You see, out there you have all these reviews where just a few real world load test are being done by using a high-end computer system. In their conclusions they are indeed correct with the statement that power supply X can keep a high-end system running stable for a period of Y hours, at sound level Z. We have had such articles too in the past but we quit doing them because we know there is much more to testing a PSU than seeing how the 3/5/12V rails behave under load.

For starters, define a high-end system, define mainstream, and how can you possible be sure that such a system can really push your PSU? Without clear numbers you are only guessing. Today we had the ability to program the load per volt rail at very high precision; we could read the current flows and calculate the power usage and efficiency of the tested units. We could honestly and accurately state that a power supply advertised for X Watt is able to actually do it (or fail to do so in some cases), and what efficiency it maintains.

There is much more to reviewing PSU's, we had the ability to analyze the inrush current, the booting process, transient response if we wanted, heat, voltage levels, power factor, ... the list goes on, however time was running out and we chose to limit the amounts of tests to be able to hook more units to the load tester and have more data to show you from different PSUs.



Coming back to our test results, we were astonished by some of them. For example we could properly stress the Cooler Master Real Power 620 up to 850W without it shutting down or burning down or anything. Completely different from what we saw with the low quality no-name units, these didn't even deliver the stated currents and stopped working at roughly 80% of their maximum rated power. They also lacked proper power factor correction and compared to quality builds they were simply not good enough. The Stability Power unit even scored as low as 66% efficiency in one of our tests. In contrast, the Cooler Master UCP 900W scored fabulous, we saw 90% efficiency which certainly deserves a high-end recommendation:


CoolerMaster UCP 900W

Both Real Power M 620W and Silent Pro M 500W performed beyond their specifications, with the Silent Pro having a small lead in efficiency, the price difference between these two is small, Real Power M 620W: €79, Silent Pro M 500W: €89. Both can easily make up part of a quality budget build and deliver enough juice to today’s high end gear.


Cooler Master Silent Pro M 500W & Real Power M 620W

We are sure to return to Venlo with a new batch of power supplies to torture, we were promised some alone time with the load test gear at our next visit so we could really delve into the details, with any unit we bring along, so you can expect more PSU reviews coming your way here at Madshrimps.

We hope you liked this article and how we tested, before you go let us thank Cooler Master for letting us turn their knobs and overload their products. Special thanks go out to Marloes for the tour around the facility, René for all his help during the test sessions, and Ron for his technical insight behind the Cooler Master design philosophy. Until next time, take care!