Noctua's DX line CPU coolers have become a default choice in premium grade quiet cooling solutions for Intel Xeon processors. The NH-D9 DX-3647 4U features a larger, custom-designed contact surface and supports both square and narrow type LGA3647 platforms. Based on the proven, 92mm size NH-D9L heatsink and equipped with two of Noctua's award-winning, PWM controlled NF-A9 92mm fans (high-efficiency 2500rpm version), it combines strong performance with excellent compatibility for 4U systems and other space-restricted applications. Topped off with the professional SecuFirm2™ mounting system and pre-applied NT-H1 thermal compound, the NH-D9 DX-3647 4U forms a complete premium quality package for quietly cooling LGA3647 based Xeon workstations and servers.