Patch 5 or v1.0.4.0 is regarded as the best performing iirc. Plus it's the best version to use with some of the ENB Series visual mods, like this :
http://www.youtube.com/user/dpeasant3#p/u/5/qgAvfAtyPEo
Or this one that works will all versions of GTA IV afaik :
http://www.youtube.com/user/DKTronics70#p/u/10/Cw2V_HzLyTM
dpeasant3's mod looks prettier, but is not quite as straightforward to get up & running as DKTronic's mod & will impact your fps.
Versions from 1.6 onwards changed the shadowing method so they look prettier / smoother & use less vram, but they cause a noticeable performance hit.
http://www.youtube.com/user/dpeasant3#p/u/5/qgAvfAtyPEo
Or this one that works will all versions of GTA IV afaik :
http://www.youtube.com/user/DKTronics70#p/u/10/Cw2V_HzLyTM
dpeasant3's mod looks prettier, but is not quite as straightforward to get up & running as DKTronic's mod & will impact your fps.
Versions from 1.6 onwards changed the shadowing method so they look prettier / smoother & use less vram, but they cause a noticeable performance hit.