OCZ ZX850W Power Supply Review

Testing consisted of loading many instances of Prime95, 7-Zip archiving, several Steam titles (minimized), rendering a blu-ray title to iPod format, and FurMark running full screen at 5760 x 1200, 8X MSAA.  This is a considerable load for any computer and would represent at least a base minimum that a typical user might do on a computer.

First on initial boot a peak measurement of 167watts idle at windows logon screen was taken with Kill-A-Watt electricity usage monitor.

With the test running for 1 hour a peak measurement of usage was 485watts.  The system was then let off for 1 hour, booted up and that same battery of programs was loaded up, this time with a peak measurement of usage was 491 watts.

Now some notes about this type of testing.  The Kill A Watt used has a published accuracy of 0.2%, meaning for every 100 watts measured the actual usage could be in the range of 100 watts +/- 0.2 watts.

Another common test method is to hook up a multimeter to the 3.3V, 5V, 12V, and -12V connections to check the voltage stays within range.  This is a useless exercise as the PWM, Pulse-width modulation, control circuitry detects and corrects the tiny changes in voltage that occur in the span of milliseconds and corrects these fluctuations.

So what can be said about the OCZ ZX850W Power Supply from a test perspective?  Well the unit ran flawlessly for 4 weeks performing hundreds of hours of video encoding, heavy CrossFire graphics usage, and general day-to-day tasks. A common problem with cheap or faulty power supplies is they function fine at first but after some initial heavy loading or extended use begin to operate so far outside acceptable voltage or temperature ranges that systems experience degraded performance or complete instability. While using the i7 based system powered by the ZX850W Power Supply I did not experience a single instance of instability such as a blue screen (BSoD) or freeze. This does not mean the PSU is perfect, but goes to show OCZ has developed a quality product subject to good quality control mechanisms.