High-end power supply for next-gen graphics cards with maximum efficiency Dark Power 13 is without a doubt the most efficient power supply series from be quiet! Thanks to its extremely high efficiency of up to 95.8%, the power supply has achieved 80 PLUS Titanium certification, making the Dark Power 13 series an example of efficiency. In addition to the unrivalled operational efficiency, the patented frameless fan concept with a Silent Wings fan enables optimum cooling and almost inaudible operation under normal load. The overclocking key enables manual switching between multi-rail and single-rail operation.