I read awhile back that Leopard takes advantage of the XD bit on Intel processors (I have core 2 duo macbook) for security, but then I saw some commentary about how Snow Leopard was going to *actually* use the XD bit. Anyone know the story? Did Leopard fail to really use it? And is it (like w/ windows boxes) something I have to go into the BIOS to enable? I can't figure out how to get into my Macbook bios to turn it on, nor can I see in Leopard if it's enabled.