Well Parky, you asked, so I'm going to try to answer!

The way I think about PAE is that it kinda works a bit like a stonking great in-memory pagefile might. It doesn't change the game for 32-bit applications, but it does give the OS more headroom to manage them.

Without PAE, any memory over 4GB can't be "seen" by the OS itself, so it can't be used.

With PAE, the memory manager