I have another problem now though...

After updating the rig to the fall creator's update - and new nVidia drivers 391.01 I lost 25% hashrate (from 1350 to 1040 kH/s). I have been running the high priority miner, using parameters -i 5 -c 4. I also now seem to get a lot of "Share rejected, invalid job ID" messages. No idea if related or what's going on. Any ideas?