I agree, if you're not touching the memory limits of 32bit, there is no reason to do 64bit. Because 64bit applications have to pass 64bit addresses to read from

I agree, if you're not touching the memory limits of 32bit, there is no reason to do 64bit. Because 64bit applications have to pass 64bit addresses to read from memory it is slower than 32bit which only have to pass 32bits of data (simplified but true).