Our load tests utilize a couple of FAST ATE active load testers, and a variety of other equipment such as an oscilloscope, power conditioner, temperature probe, and a power consumption meter. You can read more about our standard testing approach here.
The tests performed are based around six conceivable setups that are out there, and progressively load down the PSU up to the power supply's limits, or 1000W; whichever comes first. Since our test equipment's limits are higher than that of the XFX XTR 550W power supply, we can test it to the maximum.
The tests above represent typical loads that we have measured from various systems, and are meant to give a rough idea of where your computer might fall in line with our tests. Please keep in mind that each system is different, and actual loads can vary greatly; even with similar hardware.
Let's start by taking a look at the voltages, to see how well this unit did during testing. Starting with the 12V rail, we see 2% regulation from start to finish, with a total drop of .13V. The 5V rail managed to stay within 2% of specification, with a total drop of .05V from start to finish. Moving towards the 3.3V rail, we see that regulation was within 1% of specification, with a total voltage drop of .03V.
DC Output quality for the XFX XTR 550W was good, and well within specifications. During Test One, we saw 13mV of noise on our scope. When we increased the loads in Test Two, the ripple climbed to 18mV at just over half load. During Test Three, under a load of 550W, the oscilloscope showed a maximum of 26mV on noise on the 12V rail.
The XFX XTR 550W is rated for 80 PLUS Gold efficiency. This means that the power supply must perform at 87% / 90% / 87% efficiency, at 20% / 50% / 100% loads respectively. As you can see, the XTR 550W passed on our bench, and wasn't close to failing at any point.
I'm always happy when an XFX power supply shows up on my doorstep. I have the utmost faith in that whatever it is, it will be a quality unit. Even though this is the lowest wattage unit that we've tested from them, I was confident from the start that it would pass with flying colors, and that is exactly what the XTR 550W power supply has done. Only once along the lines of testing was this unit a disappointment, and my conversation with XFX makes me confident that it will be resolved shortly.
The disappointment that I speak of is the limited availability of the unit. Having only a few places that sell the unit is bad for competition and prices as far as the consumer is concerned. Once the XTR has a little bit deeper market penetration, it will be a near perfect unit. It has great performance all the way around, as displayed by our test results, and it did so without as much as a hiccup. Add in the low price for a fully modular Gold rated unit, along with their five-year warranty, and you've got one hell of a formula for success. It won't be too long, and you will start to see this baby showing up in all sorts of single GPU gaming rigs, as it represents the perfect balance between price, performance, and features for a sub-700W power supply.