I definitely have a x64-based PC (running bootcamp), I downloaded the above file, and put it in my beyondthesword folder (running Civ4 through Steam), and opened the 4gb_patch, and linked it to the "Civ4BeyondSword.exe". I ran the game through steam, but haven't noticed a performance improvement in turn time loading. Do I need to run it through the .exe directly in the beyondthesword folder?