Left 4 Dead 2 System Requirement

These are the System Requirement of Left 4 Dead 2:

Minimum System Requirement:
OS:Windows XP,Windows Vista,Windows 7
Processor:Intel Pentium 4 3.0GHz or higher
RAM:1GB (2GB for Windows Vista and Windows 7)
VRAM:128MB
DirectX:9.0c
Hard Disk:7.5GB

Recommended System Requirement:
OS:Windows XP SP2,Windows Vista SP1,Windows 7
Processor:Intel Core 2 Duo 2.4GHz
RAM:2GB
VRAM:256MB
DirectX:9.0c
Hard Disk:7.5GB