Try the lowest settings and then go up from there. Then you will know what you cant use.
My RIG:
Manufacturer: *cYber Moding

Processor: AMD Phenom X4 2.5GHz 2000MHz,2MB/2MB
Memory: 8046MB RAM
Hard Drive: 250 GB
Video Card: EVGA GeForce 9 Series 9800GX2 BlackPearl
Monitor: Asus 4M/s
Sound Card: Razer Barracuda AC-1 7.1
Speakers/Headphones: Razer Barracuda HP-1 GamingHeadset
Keyboard: Razer Tarantula Gaming Keyboard
Mouse: Razer Copperhead
Mouse Surface: Razer Mousepad
Operating System: Windows XP Home Edition (5.1, Build 2600) Service Pack 2 (2600.xpsp_sp2_rtm.040803-2158)
Motherboard: ASUS M2N-E SLI DELUX
Computer Case: Thermaltake VH600LBWS Armor+ Full-Tower ATX Case