Dark Power Pro 11 550W is be quiet!’s most advanced PSU ever. With 550W of continuously available power and an overclocking key that switches between four-rail and single-rail operation, it has sufficient reserves to support any multi-GPU or multi-CPU system you could want to build. be quiet!’s virtually inaudible Silent Wings 3 fan and an unparalleled array of noise-reducing enhancements make it the quietest PSU in its category, perfect for powerful applications that nevertheless need significant quietness. And its full bridge power topology earns it one of the highest power efficiency certification available — 80 PLUS Platinum