Published: April 8, 2008 | Source: OCZ | Author: James Napier

OCZ EliteXStream 1000w ATX PSU

Load Testing

To provide our readers with the most accurate results, Overclock3D uses a custom built PSU load tester on all reviews. This not only gives much more reliable results than the testing methods employed by other sites, but also allows for all current and future review results to be compared side-by-side.

Note: Due to a limitation with the power supply testing hardware, the maximum load that we could place on the EliteXSream across each of the three rails listed above was 919w. However, despite having a shortfall of 81w against the units maximum rated output of 1000w, the tests still give a good representation of how the unit performs under full load.

The first thing we notice from the results is that under 0w load, each of the rails on the unit are extremely close to their ideal +12v, +5v and +3.3v values. This just goes to show that OCZ have faith in the EliteXStream to hold it’s voltages under load, and thus do not need to “overvolt” the rails to compensate for poor voltage regulation like a lot of other manufacturers.

Even at a load of 919w, the EliteXStream manages to stay well within ATX guidelines of Â±5% with the largest fluctuation exhibited on the +12v rail being only 0.10v

Efficiency Calculations

Efficiency tests are performed by measuring the wattage consumed by the power supply at the mains (Mains Draw) against the power consumed by the OC3D power supply stress tester (PSU Load). These results may not be 100% accurate, but have proven to be extremely close to results obtained from professional equipment.

As discussed over the previous pages, OCZ rate the EliteXStream at an “Ultra-high” efficiency level of 82%. While this may not be as impressive as the 85-87% efficiency we’ve seen on many other units recently, the EliteXStream does live up to its specifications managing a full 82.35% efficiency at 919w.

Temperature vs Noise Output

As with all components in the modern computer system, the performance of a PSU can be directly affected by heat. Excess heat inside the PSU can easily have a negative effect of the maximum power output of the unit and lead to voltage instability. For this reason, Overclock3D includes temperature recordings taken from the PSU’s exhaust using a thermal probe to highlight any potential issues that the PSU might have obtaining its rated output.

While keeping the temperature of a PSU under control is often just a case of increasing the speed of a fan, this can have a negative impact on noise levels. Therefore, Overclock3D also records the dBA output of the PSU (from a distance of 30cm) in order to gauge it’s suitability for use in a silent environment.

While most high-powered PSU’s have trouble maintaining low noise levels when under heavy loads, the EliteXStream managed this effortlessly with noise output only rising by 7.5dBA from idle to 919w load. Temperatures inside the unit were also extremely good with the unit staying well under 40Â°C (ambient temperature of 19Â°C).