Originally Posted by 306maxi 
All the PAE switch lets you do is see the RAM. The OS will still only address 4gb of ram in total and will not use any additional RAM above this although you'll be able to see it.
Nope, it allows you to use the RAM / addressing space on a supported OS
Physical Address Extension - Wikipedia, the free encyclopedia Originally Posted by dangel PAE is a hack - go 64bit it's the only true way to use all the memory properly. Full Stop. Period. As in THATS YER LOT.
This has been discussed soooooooo much here.
Yup
Hack or not though, if it worked on XP32, most people would be happy enough with it. Although its just a waste having all these 64bit CPU's and not utilizing them. Its a shame XP64 wasn't more of a success.