Asus Z9PH-D16 - Manual (Page 32)

2-14 Chapter 2: Hardware information
2. Twist each of the four screws with a Philips (cross) screwdriver just enough to
attach the heatsink to the motherboard. When the four screws are attached,
tighten them one by one to completely secure the heatsink.
2.3.2 Installing the CPU heatsink
To install the CPU heatsink:
1. Place the heatsink on top of the installed CPU, ensuring that the four
fasteners match the holes on the motherboard.
Tighten the four heatsink screws in a diagonal sequence.
A B
B A