NEC Server 140Rc-4 - Manual (Page 346)

9-60 Upgrading Your Server
10. Aligning the pins of the CPU with the socket, insert the CPU slowly and gently into the
socket.
IMPORTANT: Be aware of CPU direction. Pin layouts on two
corners among four differ from others to prevent an incorrect insertion.
Confirm the pin mark and pin layout on the socket, and insert the CPU
correctly.
11. Push the CPU lightly to the socket, and push down the lever to secure the CPU.
12. Put the heat sink on CPU.
Pin marks