360° View - Alpha PAL-8150 Heatsink Information on Frostytech's test methodology is available here.
	The Heatsink Fan: The 80x80x25mm fan spins at 4000RPM and generates about 58 dBA at full tilt. The fan is mounted upside down so warm air is exhausted out from the heatsink at the top. The fan draws power from a standard 3-pin motherboard fan header which supports RPM monitoring. Alpha include a set of shorter screws so a 15mm thick 80mm square fan may also be installed.
	Heatsink Top: With the fan removed from the body of the Alpha PAL-8150 heatsink we can see the 5mm plenum created above the tips of the pin-fins by the aluminum fan shroud. Each hexogonal pin measures 2mm in diameter, with about 2mm spacing in between. The screws used to attach the fan are fixed into the base of the heatsink, and accommodate 80mm sized fans only.
	Heatsink Side A: The aluminum fan shroud blocks off the upper half of the pin-fins so cool air is forced to enter the heatsink by the base of the pins. There is an opening 22mm high all the way around the perimeter of the Alpha PAL-8150 for air to be drawn in by the exhaust oriented fan. The pins are 41mm in height, and the base of the heatsink 9mm thick. When you install the PAL-8150, it's helpful to remember that the fan shroud and fan are fixed to the heatsink after it's installed onto the motherboard. One of the two spring tensioned screws can be seen here.
	Heatsink Side B: The long screws used to hold the fan in place use a really fine metric M3 thread pitch so be careful not to loose any of them.... replacements are difficult to find. The 104mm long Alpha APL-8150 cooler does not use the stock K8 heatsink retention frame, so be sure to remove that first.
	Heatsink Base: The 3.5mm thick copper base insert is machined quite flat in both axis, but not perfectly so. Along its length there is a very slight curvature which is noticeable against an engineers straight edge. Some good quality thermal compound will easily fill the void created at the edges of the processor IHS. The face milled metal has a surface roughness of ~8 microinches.