With PT 11 HD your looking at WIN7 (Best Bet)
http://avid.force.com/pkb/articles/e...tibility-Chart
Your card should have no problem running in the X79 board....it should be gravy.
I would personally upgrade my CPU....but that's just me.
I ran that board (UD5 actually) with a 8 Core E5-2687W chip for quite awhile...and it's a nice chip but I see much more power in the 6th gen i7's.
I upgraded my Hard Drive also to a M.2 drive and it's a world of difference.
i think most people would be happy with the power of a i7-6850....
just my $0.02.