If you are using Windows XP Professional X64 and have an AMD 64 Bit processor, this patch is for you.
Ubisoft have released a new patch for Far Cry to improve performance for users with the new Windows XP Professional X64 who have an AMD 64 Bit processor. As well as improving the game's performance, the patch improves the visual quality of the game, allowing for longer draw distances, enhanced textures and more objects with real-time physics.
You can find out more about the Far Cry 64 Bit patch here.

