Minimum system requirements for GTA: San Andreas By RockstarGames
Windows 2000 (with Service Pack 1 or higher)  
Windows XP   (with Service Pack 1 or higher)
Hardware:
Processor: 1Ghz Pentium or AMD Athlon 
RAM: 256 MB RAM 
Video Card: 64MB Directx9 compatible (GeForce3 or better) 
Soundcard: Directx9 compatible 
DirectXOM: 8x DVD ROM Drive 
Hard D Version: DirectX 9 
DVD-Rrive: 4.7 GB free hard disk space 
Peripherals: Keyboard and mouse
Recommended:
Processor: Pentium  4 or Athlon XP 
RAM: 384+ MB RAM 
Video Card: 128MB Nvidia GeForce6 or better) 
Soundcard: Directx9 compatible surround sound card (Sound Blaster Audigy 2 Seried Recommended) 
DVD-ROM: 16x DVD ROM Drive 
Hard Drive: 4.7 GB free hard disk space 
Peripherals: Keyboard and mouse