Huh I finally bough that card and ran GTA IV on following settings at 14-18 fps: (no overclock yet)
Resolution 1280×720
View distance 29
Draw distance 55
Vehicle density 33
Shadow density 4
Also important part that was my auto configuration and GTA IV gives same config for its recommonded requirements.... and u believe or not my friend played GTA five on lowest possible settings with 9-10th fps.