New 314.07 drivers seem to have fixed the problem for me, everything works just like before 310.70. That is unless I didn't notice some Premiere update.
Unfortunately the fix suggested here didn't work for me, I guess it was because I'm running multi-monitor setup and only way I got Premiere working again was to use Software rendering or switching back to 306.97 drivers.
According to NVIDIA program settings Premiere is using "All" CUDA-GPUs now and GPU usage hops up and down synchronously in PrecisionX, so perhaps there is some truth in it.