I ran the 64-bit version of Far Cry on my Win XP 64. I convinced myself it looked better, but I doubt it actually did.
Edit: Huh, I guess it did look better. From the 64-bit patch notes:
Optimized and refactored code to take advantage of 64-bit architecture.
Two AMD64 exclusive multiplayer maps – MP_Stronghold and MP_Gorge
Added Offset bump mapping support.
Added higher resolution textures and objects.
Increased some viewing distances.
Updated the Pier level with new content.
I ran the 64-bit version of Far Cry on my Win XP 64. I convinced myself it looked better, but I doubt it actually did.
Edit: Huh, I guess it did look better. From the 64-bit patch notes: