Mac Pro (Early 2008) Take Apart — Processor Heatsinks for 2.8 and 3.0 GHz Processors 74
Using a long-handled, magnetized 3 mm athead hex screwdriver, loosen the four captive 5.
mounting screws for the lower processor heatsink in the order indicated below.
Carefully tilt the heatsink so that it clears the bottom lip of the enclosure and then lift the 6.
heatsink out of the computer.