The Heatsink Fan:
The Thermalright Ultra-90 heatsink is built to work with a 90x90x25mm fan that spins in the region of 1500-2500RPM. Anything big, slow, and quiet will suit the Ultra-90 just fine. Owing to the design of the heatsink, and the fact that the fan is clipped on with wires, there is absolutely no protection from errant wires being sucked into the fans' impeller. Make sure you have your wires well routed when installing this heatsink in your chassis. Each nickel plated aluminum fin measures 0.6mm thick, and is spaced 2.0mm apart from the next. The fins have an overall size 102 x 38mm. The three nickel plated copper heatpipes are 6mm in diameter, and extend from the base up through all the fins. All joints are soldered.

Heatsink Top:
Looking from the top down, we can see how Thermalright have modified the aluminum cooling fins with winglets. The leading and trailing edges are alternatively bent 15° up and down. When a 90mm fan is installed, a 5mm plenum is created behind it owing to the curvature of the fins. The three 6mm diameter copper heat pipes are positioned towards the outer edge of the cooling fins. This puts them in the vicinity of the highest airflow from the fan, leaving the center portion of the cooling fins open where there is the least amount of airflow.

Heatsink Side A:
The Thermalright Ultra-90 heatsink is only 46 mm thick, but it stands 147 mm tall. The cooling fins are elevated above the socket 40 mm for clearance of adjacent capacitors, northbridge heatsinks, etc. The three copper heat pipes are positioned side to side on the copper base block. This ensures that the maximum amount of heat is absorbed from the CPU integrated heat spreader, and transferred to heatpipes in as short a distance as possible. The base is capped off with a 50mm wide aluminum section that provides rigidity and strength for the CPU clamping bracket. There is a small 8mm round hole in the top of this block to align the brackets into, and it also prevents the heatsink from sliding out from underneath of its clip.

Heatsink Base:
The nickel plated copper portion of the mounting base measures 40 mm by 40 mm. The overall size of the base is 50 mm by 40 mm. The copper base plate averages 2.5mm thick over the heat pipes, in both sections are soldered together for optimal thermal transfer. The copper is machined flat, and very smooth. Surface roughness is on the order of ~8 microinches, which is considered excellent. The aluminum support is slightly proud of the copper base, but at least the surface is perfectly flat both axis.