Right now I'm running a Ref 780 Ti.
I will be switching back to 2 780s in the next few days.
Rest of the specs
3930k
asrock Extreme9
32gb Samsung Wonder
Win7 Ult x64
Did you put client-type=advanced in the shortcut, and open it through that shortcut?
Have you tried deleting the work and trying to re-download the workunit (by opening up F@H once you close it completely (Ctrl+Alt+Delete) and deleting the 00, 01, 02... (depending on how many devices you are folding with) folders in C:/Users/You/AppData/Roaming/FAHClient)?