Of course
http://forums.steampowered.com ... s/showthread.php?t=761829
This is the list of command lines of the game, and since I couldn't find a place explaining how to use them (this link's explanation is wrong, it didn't work for me), I'll explain it:
1) Go to the GTA IV installation folder (usually C:\Program Files\Rockstar Games\Grand Theft Auto IV)
2) Create a new text file:
commandline.txt
3) Open it and place the commands you want to apply on the game, following this rule:
-command string
Note: Some commands don't need a string.
If you want to put more than a command, all you have to do is to put a space between the last command's string and add the other command (in the same line):
-command string -command2 string2
There's no command limit.
4) Save the file and then open the game. Editings made with the game running won't be applied until the game is restarted.
The command line I mentioned is
-availablevidmem string . Its string is a multiplier, so 2 = video memory x 2.
I have 512MB of video memory too but I only have 2GB RAM, so I'm using "2" multiplier so it uses the vmemory plus 512MB of RAM for graphics (remember the game already uses some RAM for its engine and game files, so people with low ammount of RAM shouldn't set it to use the whole RAM ammount). It's not your case though
Note: I don't recommend using the commands "nomemrestrict" and "norestrictions" because they can mess the game settings and cause "pop-ups", random texture disappearing etc. Using these two commands alone to set higher graphics on the settings won't make the game use RAM for graphics.