HI All
Shall try to giv a explanation watt this System requirements means 
Operating system: Windows XP (Min. service pack 2), Windows Vista or Windows 7. 
32 and 64 bits OS supported 
Memory: 2GB (Windows XP) or 3GB (Vista or Windows 7) 
This is DDR2 Memory and if you have DDR3 thats better and dos run the game better to
Processor: 3 Ghz P4 Intel or AMD equivalent processor 
this mean a on core P4 CPU, if you have a dual core quad core I3, i5 or a i7 CPU well that means you have more power in you processor so in those you can be a bit under 3 GHz 
a i3 CPU with 2,5GHz a i5 CPU with 2,2 GHz or a i7 CPU 2,0 GHz should run the game ok or AMD equivalent processor 
Video card: Geforce 8800GT or ATI Radeon 4850 with 256MB ram (At least Shader model 3.0) 
You most have at least this card and if you go higher on the power scale better will the game and graphic be 
Hard disc space: 3,5GB 
Drive: 4x PC DVD-ROM 
Input controllers: Mouse with scroll wheel 
Sound: DirectX 9.0c compatible 
DirectX: Version 9.0c 
Controller: Optional controller support DirectX 9.0c compatible 
Internet: Broadband Internet connection required for Multiplayer