360° View - Noctua NH-U9B Heatsink Information on Frostytech's test methodology is available here.
The 92x92x25mm NF-B9 fan at the heart of the Noctua NH-U9B heatsink spins at 1600RPM by default. Optional in-line resistors can reduce fan speed from that level to 1300RPM or 1000RPM if quieter operation is desired. A standard 3-pin motherboard header provides power. The nine bladed fan is ships without a fan grill. A second fan, 92mm or 80mm can also be attached to the other side of the heatsink. The nickel plated aluminum fins measure 0.5mm thick and are spaced 1.75mm apart.
The Noctua NH-U9B stands 120mm tall. Its nickel plated aluminum fins are all soldered to the four 6mm diameter copper heat pipes which rise up from the base. The first fin from the base up is elevated 32mm to give capacitor clearance. The copper portion of the base is about 4.5mm thick. The Noctua NH-U9B base is shown here without the processor specific mounting hardware installed.
The base of the Noctua NH-U9B heatsink is fabricated from a block of nickel-plated copper to which all four copper heatpipes are soldered. The base has a machined surface finish, done with a slight ridge texture. The metal is very slightly concaved at the center, not enough to require lapping. Surface roughness is ~48 microinches, which is good. The portion of the base that comes in contact with the CPU measures 40x38mm. Looking at the top of the Noctua NH-U9B heatsink we see the tips of the four 6mm diameter U-shaped copper heatpipes. The aluminum fins are roughly 96 x 65mm in size. The tabs on either edge are for the wire fan clips to lock into.