Asus Xeon 5U Rackmount Server AP1720-E1 - Manual (Page 21)

2-5 ASUS AP1720-E1 barebone server
2.3 Central Processing Unit (CPU)
The motherboard comes with dual surface mount 604-pin Zero Insertion
Force (ZIF) sockets. The sockets are designed for the Intel
® Xeon™
processors in the 604-pin package with 512KB L2 cache.
Socket for CPU1
Socket for CPU2
If installing only one CPU, use CPU socket 1 to ensure system stability.
Before installing the CPU, remove the chassis fan attached to the inner
side of the rear panel to allow enough space for the installation. Refer
to section “2.10 Removable components” for instructions.