Working with our APC SmartUPS SC 620, this PSU was stable at loads up to 407 watts when powered by the mains but could not switch to the UPS’s batteries even at 280 watts. That’s the worst result in this review.
Cross-Load Voltage Stability
First we tested the PSU at its specified output power of 500 watts.
The +12V voltage is no more than 2% off in the typical load range. The +5V voltage is within 3% of the required level. The +3.3V voltage can deflect by up to 4% when the computer is idle.
When the PSU is “overclocked” to 600 watts, its voltages are just as stable as at 500 watts.
Output Voltage Ripple
Since this test depends on the output power, we carried it out at the PSU’s default 500 watts and in the overclocked 600W mode.
The high-frequency voltage ripple doesn’t change depending on the operation mode and meets the requirements of the industry standard. The Stryker STR-500 is inferior to the Seasonic X-460 in this test, though.
The low-frequency ripple doesn’t depend on the operation mode, either. It is within the norm, too.
Efficiency and Power Factor
This test was also carried out in the PSU’s default and overclocked operation modes. The 500W mode comes first:
The efficiency is 92.4%, 93.1% and 91.3% at the reference loads of 20%, 50% and 100%. This agrees with the 80 PLUS Platinum requirements this model is certified for. The peak efficiency of 93.3% was achieved at a load of 320 watts.
And now the overclocked mode:
The PSU is 91.9%, 92.9% and 90.7% efficient at the loads of 20%, 50% and 100% now. In fact, this is not Gold but Platinum again. Just an excellent performance!
The power factor is about 98% at high loads, which is but slightly lower than the best implementations of active power factor correction.
The standby voltage is no more than 2% off the required level.
The Kingwin Stryker STR-500 features impressive efficiency, very high wattage (for a fanless model) and handy cables. It doesn’t seem to have any downsides, except for its high price. But we guess a silent Platinum-certified 600-watt PSU just can’t be cheap.