GTA 3 / VC = Err..... 800x600x16 at medium setting
GTA SA = 800x600x16 at low settings
GTA 4 = Nope.
Fast and easy for ya. =P
GTA III would be more like 1024x768x32 @ medium.
My 16mb ATI Rage 128 Ultra could handle that and it was from the DirectX 6 generation.