What drivers are you using in Linux? To use the coolbits 14 (OC'ing and Fan control) i think you need 337.xx drivers and above.
Finally got my 780 Ti running in Linux 14.04 using 337.xx driver. What a PITA. Lord knows how many units i failed (using anonymous) getting this set up.
I could not use 340.xx drivers - Insta -Failures when trying to fold.