It's not a hardware limitation. Any processor you'd want to use today supports PAE, since it was introduced with the Pentium Pro. Even if some pre-ppro box in

It's not a hardware limitation. Any processor you'd want to use today supports PAE, since it was introduced with the Pentium Pro. Even if some pre-ppro box in some utility closet is still running, its motherboard probably doesn't support anywhere near 4GB, so it's irrelevant that the CPU doesn't support PAE. Linux for 32bit CPUs supported >4GB using PAE page tables for a long time before 64bit consumer processors went mainstream. It's partially Microsoft trying to segment the market, and partially concern that a larger address space visible in a 32bit OS might/would trigger bugs in device drivers or perhaps other software. http://en.wikipedia.org/wiki/Physical_Address_Extension#Design http://en.wikipedia.org/wiki/Physical_Address_Extension#Desi... http://msdn.microsoft.com/en-us/library/windows/desktop/aa366778(v=vs.85).aspx http://msdn.microsoft.com/en-us/library/windows/desktop/aa36...