The 25x92x92mm PWM fan on the Xigmatek HDT-S983 heatsink spins at 1200-2800RPM depending on the temperature of the CPU and BIOS setting. Power is supplied by a 4-pin motherboard fan header. There is no wire fan grill to protect the impeller from errant wires inside the computer case. The three copper heatpipes are 8mm in diameter, and extend from the base up through all the fins. The joints are all unsoldered. Looking from the top down we see small dimples and the convex curve in the aluminum fins, a 4.5mm plenum behind the fan, and the tips of the heatpipes. The curve helps funnel air towards the highest temperature metal, leaving the center portion of the cooling fins open where there is the least amount of airflow.

The shape of the Xigmatek HDT-S983's fins change from a sharp convex curve to a flattened out "V" shape at the rear. The whole heatsink stands ~136mm tall, with the bulk of it elevated 36mm above the base to provide clearance for adjacent devices on the motherboard. The base is capped with a 12mm thick aluminum section to provides support for CPU clamping brackets. The aluminum fins are 0.4mm thick and spaced 1.75mm apart. The rubber mounting posts are visible here with the fan removed. The two cuts in the aluminum base are for the AMD K8 mounting clip to lock into.

The three copper heat pipes are packed closely at the base where they make direct contact with the processor. This configuration ensures that the maximum amount of heat is conducted from the CPU's integrated heat spreader to the heatpipes. The usable area of the Xigmatek HDT-S963 heatsink base is 34x34mm in size. Note how the copper heatpipes have been swaged into the aluminum base block and pressed flat. In this case the idea is not to have the aluminum base cap absorb much heat. The two screw holes are for the Intel mounting hardware to attach to.