Hi thanks for your effort I read this initially and there isn't a single difference between the original board and the two revisions nor is there any clue on the internet. Either way it's probably not even an issue. I've installed the board and have the system up and running. In most respects I like the board it's obviously good quality and the dual bios is a bonus as is the digital power management the only thing I'm not sure is the software and bios interface it's not bad just not as good as the asus board software it's replaced., which was very easy to use but comprehensive. Still it's like all things you get used to it. Still can't get the I5 HD 400 graphics to display but will have a look at settings to see if I have forgotten to do something obvious.