Was looking on play.com for GTA4 and found the minimum requirements:
Windows XP with SP3 / Vista with SP1
1.8GHz Intel Core 2 Duo, 2.4GHz AMD Athlon X2 64 or equivalent
1GB RAM (1.5GB for Vista)
16GB HDD Space
256MB nVidia 7900, ATi X1900 or equivalent
DVD-ROM Drive
Internet connection required for installation and online play
They seem pretty steep for minimum, more of a recommended. Especially the graphic cards, the 7900 is still quite a high end DX9 card.
				
			Windows XP with SP3 / Vista with SP1
1.8GHz Intel Core 2 Duo, 2.4GHz AMD Athlon X2 64 or equivalent
1GB RAM (1.5GB for Vista)
16GB HDD Space
256MB nVidia 7900, ATi X1900 or equivalent
DVD-ROM Drive
Internet connection required for installation and online play
They seem pretty steep for minimum, more of a recommended. Especially the graphic cards, the 7900 is still quite a high end DX9 card.
My Computer
System One
- 
                
				 
	
			
				
- Manufacturer/Model
 - Custom Built
 
- CPU
 - Intel Core 2 Quad Q9550
 
- Motherboard
 - XFX MB-750I-72P9 NF750i
 
- Memory
 - 4096MB Corsair XMS2 PC-5400
 
- Graphics card(s)
 - ASUS Nvidia Geforce GTX470
 
- Sound Card
 - ASUS Xonar DX
 
- Monitor(s) Displays
 - Dell 24" S2409W & Dell 20" E207WFP
 
- Screen Resolution
 - 1920x1080 & 1680x1050
 
- Hard Drives
 - 750GB Western Digital Caviar Black & 500GB Samsung
 
- PSU
 - 750 watt Thermaltake Toughpower
 
- Case
 - Coolermaster Dominator 690 Nvidia Edition
 
- Cooling
 - Zalman CNPS9700-NT Cooler, 6x 120mm Chassis Fans
 
- Mouse
 - Logitech G5 Laser Mouse (2007 edition)
 
- Keyboard
 - Logitech G11 Keyboard
 
- Internet Speed
 - 100Mbps
 
- Other Info
 - abit airpace 54mbps wireless PCI-E x1 card