The Fractal Design Tesla R2 650W power supply bears an 80Plus Gold certification, therefore its high efficiency did not come as a surprise to us. Our instrumentation recorded a maximum efficiency of 92.4% at 50% load, with a supply voltage of 230V AC, and a minimum of 89.5% at maximum load. The efficiency drops by about 0.9% when the input voltage is switched to 110V AC.
Acoustically, the Fractal Design Tesla R2 650W unit exhibits rather strange behavior. Up to 50% load, the speed of the fan remains minimal and the noise levels are very low, with the power supply being essentially silent from a distance of 1m away. The speed of the fan however increases rapidly once the load requires more than 320-330W, reaching clearly audible, yet not loud sound levels.
The Fractal Design Tesla R2 650W unit maintains very low operating temperatures across the entire load range. The maximum temperature difference between the ambient and the exhaust of the power supply is a mere 4.8 degrees Celsius at maximum load, while the chassis of the power supply does not even get warm to the touch.