HP simply "cheats" us, the customers to buy new motherboards that are having the SAME EXACT hardware but they play with the BIOS BootBlock Date and ship it as a revision number!!
I wrote about it in my last reply here:
I will try my best to warn everyone i know not to buy HP products from now on due to this way of cheating until they update the z620 BIOS file in the driver site to allow me to upgrade my CPU since it has the same hardware specs that the V2 Ivy Bridge CPUs run on!!