I believe I read that you need either the P35, G33 or nForce 680i chipsets for the 1333Mhz FSB Maybe if you downclock the CPU?
^Taken from a couple sites Either Asus is wrong/false advertising, or they can do it with a simple BIOS update.
Max official BUS speed according to Intel specs for 965 that I can find published is 1066MHz - however, we know that the chipset is good for over 2000MHz (because several mobos will do that overclocked). As for will the older mobos run them as well as P35 imo they should apart from the improvements in P35 (like the better memory controller).
you can run 1333MHz FSB chips in P965 boards natively if there is a BIOS update to support the new CPUs... We've certainly been running 1333MHz FSB chips in boards that aren't supposed to officially support the chips. Intel's BadAxe 2 (with a 2006 BIOS - forget the exact version) runs them fine, for example.