Purge Jihad is intentionally designed with low system requirements. It should play very well even on older systems.

SYSTEM REQUIREMENTS (MINIMUM)
Supported OS: Win98 / Win98 SE / Win ME / Win 2000 with the latest service pack / Windows XP
CPU: PIII 500 Mhz or equivalent
Memory: 128 MB (256 MB for Windows 2000 or XP)
Video: 3D Accelerated video card with 32 MB
Sound Card: 16-bit Sound Card
HD Space: 700 MB free
56.4k modem or broadband Internet connection is required

SYSTEM REQUIREMENTS (RECOMMENDED)
Supported OS: Win98 / Win98 SE / Win ME / Win 2000 with the latest service pack / Windows XP
CPU: PIII 1 Ghz or equivalent (or better)
Memory: 256 MB (or better)
Video: 3D Accelerated video card with 64 MB (or better)
Sound Card: 16-bit Sound Card (or better)
HD Space: 700 MB free
56.4k modem or broadband Internet connection is required