your rig is nice, but from my expierience turn off shadow density( not the actual shadows) trust me eats fps. But dont forget gta4 is heavily cpu biasd so dont b surpirsed at the occasional 20 fps (overclocking your cpu would b a great help tho)
But medium/ high should do just play with the settings untill you find one that works best for your config
If you have a 1280x1024 monitor or lower, then you'll run the game fine at low/medium settings. If you have a higher resolution LCD monitor, then you might be out of luck...
Message edited by simplyderp on 08-13-2009 at 03:48:02 AM