Both me and my wife have been having the same issue, in heavily loaded areas(Lots of other players around) or in dungons/raids. It has happened multiple times since 5.1 came out, including 3 times today in the span of 45 mins.

Both PCs are using current GPU drivers, have been reinstalled multiple times.

Makes the game almost unplayable, anytime I am tanking a raid and the game freezes or just throws a DX Error I have to restart the game and hope I make it back in time so no one is dead.

I was only able to catch a screenshot of my DX error.