Question: CPU In My Computer

Self-Build Linux Desktop:

Gigabyte GA-78LMT-USB3 (rev 5.0)
AMD FX 4300 (AMD FX 4-Core) Processor
12 GB of RAM: (2x4GB Modules) 1600MHz DDR3 & (2x2GB Modules) 1600MHz DDR3


LinuxMint
Release 13 (maya) 64bit
Kernel Linux 3.2.0-23-generic

Hardware
Memory: 11.2 GiB

Processor: 0 AMD FX(tm)-4300 Quad-Core Processor
Processor: 1 AMD FX(tm)-4300 Quad-Core Processor
Processor: 2 AMD FX(tm)-4300 Quad-Core Processor
Processor: 3 AMD FX(tm)-4300 Quad-Core Processor

I want to know, why is the first processor set to 0?

Thank you.