Halo 2 system requirements (minimum)
CPU: 2 Ghz Pentium 4 class processor (or x64)
CPU SPEED: 2 GHz
RAM: 1 GB
OS: Windows Vista
VIDEO CARD: DX9 graphics card: WDDM driver, PS 2.0/32BPP, At least nVidia 6000 or ATI x700 or above
SOUND CARD: Yes
FREE DISK SPACE: 7 GB
DVD-ROM: Yes
Halo 2 Recommended Requirements
CPU: Dual Core processor
CPU SPEED: 3 GHz
RAM: 1 GB
OS: Windows Vista
VIDEO CARD: DX9 graphics card: WDDM driver, PS 3.0/32BPP, At least nVidia 7800 or ATI x1800 or above
SOUND CARD: Yes
FREE DISK SPACE: 7 GB
DVD-ROM: Yes