@panzer22:
Are you sure you understood what PAE is used for? PAE is an extension which was introduced to allow CPUs to access more than 4 GB of RAM, by increasing the maximum addressable memory location from 32 bits to 36 bits (so a total of 64 GB RAM is addressable).

It has nothing to do with the execution prevention introduced in WinXP SP2 and doesn't make Windows more or less secure in any way. In fact, the PAE extension has been available since WinNT 4.0 SP3 came out.