I attempted to overclock my card using the 14.1 beta driver and afterburner, my 290 would no longer idle. I decided to uninstall afterburner and let it remain at the default speed (still a beast card).
I then noticed while using furmark that roughly half the time (using 1280X720 resolution and 0 AA) my frames would be 50-60, while the other half the time I would be getting 100-110 (only changing after a computer restart). Based on GPU-Z the card was under 100% load both times, although the measured core clock seems to stop at around 900 (not sure if this is normal as I am a novice).
I have just reverted back to the 13.12 driver and so far I have not had this mysterious throttle.
Any information regarding anything I have mentioned would be greatly appreciated.