I can't find any system requirements for Arma...
ARMA:
Minimum Specification:*CPU: 2.0 GHz Intel Pentium 4 or equivalent processor*
RAM: 512 MB*
Graphics card: Nvidia Geforce FX series or ATI Radeon 9500 series or higher (Pixel Shader 2.0)*
HD space: 3 GB (or more as needed for downloadable addons)*
Operating system: Windows XP or Windows 2000
Recommended Specification:
*CPU: 3.0 GHz Intel Pentium 4 or equivalent processor*
RAM: 1 GB*Graphics card: Nvidia Geforce 6800 series or ATI Radeon X800 series or higher
*HD space: 4 GB (or more as needed for downloadable addons)*
Operating system: Windows XP
ARMA II
Minimum
CPU Dual Core (Intel Pentium D 3.0 GHz, Intel Core 2.0 GHz, AMD Athlon 3200+ or faster)
Memory 1 GB RAM
Hard drive space 10 GB
Graphics hardware Nvidia Geforce 7800, ATI Radeon 1800 or faster (with Shader Model 3 and 256 MB VRAM)
Recommended
Quad Core CPU or Dual Core CPU (Intel Core 2.8 GHz, AMD Athlon 64 X2 4400 + or faster)
2 GB RAM
Hard drive space 10 GB
Nvidia Geforce 8800GT, ATI Radeon 4850 or faster (with Shader Model 3 and 512 MB VRAM)