I have an i7 2600k running stock speed and a Radeon 6970 struggling on the Dayz standalone with average settings. I bought a basic MSI 780 to use with my 2600k and then had no problems at all playing Dayz at full maxed out settings. This lasted 2 days before the 780 died and then failed to post so its been returned. A 780ti should have no problems and I can't wait to get one and get back into the same.
Not sure if it is card or manufacturer specific but my 780 had a feature built in to record perfect full-hd in-game video in the background with practically no noticeable affect during game play.