Based on Noctua's compact NH-U9 series and fitted with the award-winning NF-B9 fan and NT-H1 thermal compound, the NH-U9DO forms a complete premium quality package that provides excellent quiet cooling performance for 4U Opteron workstations and servers. The NH-U9DO's SecuFirm mounting system is fully compatible with the standard backplate and makes the NH-U9DO a simple drop-in replacement for AMD stock coolers. The NH-U9DO can be installed and rotated by 90 degrees to allow for an optimal positioning of the cooler and to avoid compatibility issues on dual socket mainboards. The SecuFirm mounting system screws directly to the standard Socket F backplate in order to facilitate the installation process. Featuring psychoacoustic optimizations and Noctua's premium-grade SSO-bearing, the award-winning NF-B9 is renowned for its exceptional quietness and long-term stability. The NT-H1 is a pro-grade TIM solution that provides minimum thermal resistance, excellent ease-of-use and outstanding reliability. Socket compatibility includes Socket K8 (including 754, 939 & 940) and Socket F (with hole spacing 88.9mm).