Based on Noctua's NH-U12P and NH-U9B series and fitted with their award-winning Vortex Control fans and NT-H1 thermal compound, the NH-U12 DO and NH-U9 DO form a complete premium quality package that provides outstanding quiet cooling performance for AMD Opteron workstations and servers. The NH-U12 DO and NH-U9 DO's SecuFirm mounting system screws directly to the standard backplate and makes the NH-U12 DO and NH-U9 DO a simple drop-in replacement for AMD stock coolers. Can be turned by 90 for optimal compatibility and positioning The NH-U12 DO and NH-U9 DO can be installed rotated by 90 to allow for an optimal positioning of the cooler and to evade compatibility issues on dual socket motherboards. Drop-in replacement for standard AMD coolers The NH-U12 DO and NH-U9 DO's SecuFirm mounting system screws directly to the standard Socket F backplate in order to facilitate the installation process. The award-winning NF-P12 or NF-B9 premium fan Featuring psychoacoustic optimisations and Noctua's premium-grade SSO-bearing, the award-winning NF-P12 or NF-B9 is renowned for its exceptional quietness and long-term stability. NT-H1 thermal compound Noctua's much-acclaimed NT-H1 is a pro-grade TIM solution that provides minimum thermal resistance, excellent ease-of-use and outstanding reliability.