The Multi-Patch replaces the GameSpy master servers and optionally forces Vsync. The Steam version is already patched.
HKEY_LOCAL_MACHINE\SOFTWARE\GSC Game World\STALKER-SHOC
To use mods with STALKER, you will first need to edit your fsgame.ltx - file found under the game's install folder.
$game_data$ = false| true| $fs_root$| gamedata
$game_data$ = true| true| $fs_root$| gamedata
Download the program at Codeplex. The program installs the mods from .zip or directly from the folder. It will warn you if there are issues with other mods combined; then you have to choose one of them.
HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\GSC Game World\STALKER-SHOC
Improves stability on systems with at least 3GB RAM by allowing the application to use more than 2GB RAM.