I am not forgetting PAE. Even if it is turned on it will not allow for Windows 32 Bit to use more than 4GB of RAM. As the final line says:
given appropriate operating system support.
That is not in Windows as much as they try to say it is. I have enabled it myself and still do not even get the correct reading in Vista let alone use of the RAM. This is the i neglect to state anything about it cause i have yet to see it work perfectly and flawlessly.