Actually, PAE only increases memory to 36 bits addressable. This is why even with PAE, Intel based x86 servers are stuck at 64 gigs of memory. And unfortunatly it is still only in 4gb chunks, so no one process can use more then 32 bits of memory. It's basicially a hack because 64 but computing kept being pushed off in the mainstream arenas. I hope one day mainstream computing isn't held back by lack of forsight. Take for example another technology that enjoys hitting barriers every year or two, IDE.

More info on PAE here.