OCZ ModXstream Pro 500w
To provide our readers with the most accurate results, Overclock3D uses a professional grade SunMoon SM-268+ ATE load tester capable of placing a sustained load of 1690w across a total of six rails (including +5vsb and -12v) on the PSU. Unlike our previous resistor based load tester the SM-268+ gives us the ability to adjust amperage loads in increments as small as 0.01A while also measuring voltages and wattage readings on-screen.
During todays tests we will be placing the ModXstream under 25%, 50%, 75% and 100% load levels and taking voltage readings at every stage. The chart below details the exact amperage load placed on each rail of the PSU at the aforementioned load levels:
| Total *||126W||252W||376W||498W|
**Total wattage is taken directly from the SM-268+ readout rather than a calculation of the amperage loads.
With testing done at the above settings, we were able to achieve the following results from the ModXstream 500w.
|+12v1 / +12v2 *||12.14v||12.05v||11.95v||11.85v|
As you can see, the ModXstream 500w has fairly good voltage regulation, with all the voltages well within the ATX specification. The voltages did shift quite a lot as we applied more and more load, with most of them going from small overvolts to a slight undervolt. However, since this is well within the 5% ATX tollerance level, it's nothing to worry about.
Efficiency tests are performed by measuring the wattage consumed by the power supply at the mains (Mains Draw) against the wattage readout displayed on the SM-268+ load tester (PSU Load). These results should offer around 99% accuracy placing them extremely close to results obtained from professional equipment.
| PSU Load||126w||252w||376w||498w|
Efficiency on the whole was rather good. The 85% achieved between 50-75% is good, but other PSU manufacturers have released models with up to 90% efficiency, so it's nothing ground-breaking. The only minor niggle is the efficiency at 100% load, where it drops to below 83%. However, it is highly unlikely that you will run a PSU that close to its limits, so it shouldn't be a concern the average user.
As with all components in the modern computer system, the performance of a PSU can be directly affected by heat. Excess levels of heat recorded at the PSU's exhaust can indicate that the cooling system is inadequate in keeping the PSU's internal temperature under control which can subsequently lead to a reduction in the maximum power output of the unit. For this reason Overclock3D takes temperature readings from the PSU's intake and exhaust areas after 10 minutes of running at each specified load level. These results can be seen below.
The temperature tests didn't give us any readings to be conerned about, with the PSU staying well within comfortable operating temperatures. The 14cm fan obviously does a great job of cooling, and the cool temperature at which the components operate should ensure a long life span.