1) The MB do support the intel XMP. Look at the manual page 2-12 as long as you enable the ausu miltcore enhancement function. But the RAM have to support the intel XMP.
2) You don't post the RAM info like the model, but as long as it has the voltage below 1.65V then it will fit.
3) XMP basically does three things. Read the review from the link. http://www.legitreviews.com/article/613/1/