Spire SPA04B4 Heatsink From All Angles
	The Fan: Rotating at 2300RPM, the 35mm thick 80mm fan you see on top of the WhisperRock IV is naturally very quiet. The fan grill is a useful addition and protects the large intake area from errant wires and power connectors. The fan draws power from a three-pin motherboard fan header.
	Heatsink Top: A single slice is cut through the center of the heatsink for the fan clip. There are four additional, smaller cuts to help with exhaust air escaping from the heatsink. Oddly, the peak in the center of the heatsink does not correspond with the location the heatsink mounts onto the processor core - it is centered on the body of the heatsink instead of over the processor core. A small spring retainer keeps the clip from floating up and out of the heatsink.
	Side A: The upper portion of the Spire SPA04B4 measures 80mm in size, but to fit on a motherboard the manufacturer made the base just 60mm is size. To do achieve this the base tapers in, and the fins are cut in a curved fashion. This makes the WhisperRock IV compatible with even the most crowded motherboard out there. The outside scalping of the fins is more for gripping than it is for any particular thermal advantages. The three-prong clip requires a screwdriver to engage, but works really well and is easy to use.
	Side B: Large screws hold the fan, and fan grill firmly in place, and since it rotates at a relatively low RPM there isn't much noise at all. The fan is suspended a few millimeters above the tips of the fins to promote better airflow. The base is 6mm thick at the edges, and rises to 13mm thick at the center. The fins of the heatsink are 1mm thick and spaced 2mm apart. It is difficult to say exactly how thick the copper is, but I would guess 3-6mm.
	Heatsink Base: The base is excellently finished and machined perfectly flat. The 30mm diameter copper disc is set into the base nicely, but we have no data on how thick the copper actually is. Curiously, the copper is centered on the heatsink instead of being centered around where the processor will actually make contact with the metal.