the game has an issue with detecting available video memory; if it exceeds 2GB (video card memory + available system RAM for textures), unpleasant bugs may occur, such as the texture quality dropping below the minimum at startup or randomly during gameplay, and in some cases, the game may crash completely at startup. I've observed this on NVIDIA cards on systems running Vista and later. Try placing the fix d3d9.dll in the game's bin folder and checking if it resolves the issue.