This is the latest official patch for the game. It is best suited for Single Player.
Although this is an official patch, it was recalled by the developers due to the extra bugs it caused. It should only be used to gain the optimal multiplayer experience from the game (most servers use v1.0006). Do NOT install this patch otherwise.
Some mods only work with v1.0004. Only use this patch if those mods have no updated version that work with newer versions of the game.
A guide on how to downgrade a copy of the game to v.10005 or v1.0004 can be found in the GOG.com Community Discussions.
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.
To use mods with S.T.A.L.K.E.R., 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.