Since you only have 4GB of ram I'd say it's rather important that you close as many background programs as possible before launching. Perhaps use a memory trimming tool, like mine
Overclocking your gpu a bit will help a lot. Also get that 1055T up around 3.2-3.4GHz. In my experience GTAIV uses about 3 cores max (though the threads may distribute evenly giving it the appearance that it's using all of your cores).
Since your system is so similar to mine, here's what my in game settings are:
1920x1080 @ 60Hz
Texture Quality: High
Reflection Resolution: High
Water Quality: Very High
Shadow Quality: High
Night Shadows: Off
Texture Filter Quality: Anisotropic x4
View Distance: 25
Details Distance: 31
Vehicle Density: 51
I also use "Disable Desktop Composition" on the GTAIV executable to free up an extra one or two MB of video ram
There are also some command line options for the main executable that you can fiddle around with.
Originally Posted by BondExtreme
Frames are almost never good in that game unless you have a $3000 PC it seems. :/
Correct me otherwise
Plays fine on my PC and it looks brilliant too. When I played it on the PS3 and the 360 I was horrified by the terrible graphics and frame rates.