Asus Crosshair V Formula/ThunderBolt - Manual (Page 34)

2.2.3. Central.Processing.Unit.(CPU)
The motherboard comes with an AM3+ socket designed for AMD® Next
Generation CPU up to 8-core, also compatible with AMD® socket AM3 for AMD®
Phenom™ II/Athlon™ II/ Sempron™ 100 Series Processors.
Ensure that you use a CPU designed for the AM3+/AM3 socket. The CPU fits in
only one correct orientation. DO NOT force the CPU into the socket to prevent
bending the connectors on the socket and damaging the CPU!
Ensure that all power cables are unplugged before installing the CPU.
2-4 Chapter 2: Hardware information