Arnoldasm, The document on the link you provided is the most current list of supported processors up to date. The page on their site is actually just a copy of ours, which is located here.  It is the current list of processors though. Hope this helps answer your question.
HI, where I can find the newest cpu support list, I only found this doc which is not from dell page a248.e.akamai.net/.../dell-poweredge-r720-r720xd-technical-guide.pdf
R720 cpu support list