Asus WS C621E SAGE Series Manual page 50

The CPU and heatsink assembly fits in
only one correct orientation. DO NOT
force the CPU and heatsink assembly
into the socket to prevent damaging the
CPU pins on the socket.
The heatsink screws are T30 models.
A torque value of 12 inch-lbf is
recommended.
Chapter 2: Basic Installation
2-2