EDIT: Aaaaaand once again: 32Bit does NOT matter! Cause 32bit or 64bit has nothing todo with performance.
I disagree with that, at least if it's meant to be a general statement. For instance, when a game exceeds the 4 GB memory barrier that comes with 32 bit applications, this has effects on the performance. However, a 32 bit application handles polygons and textures as good as a 64 bit application, so it is true that just switching to 64 bit does not magically fix all performance issues one may have.