Ditto on my rig.

Core i74770k@ 4500
ATI r9280x
16 GB RAM
Win8.1

In Citys i have FPS drops to 1 - 9, outside 25 max. up to 30 FPS.
I have done Startcommands was recommendet in Inet and recommendet Inihacks form Inet. Also i testet with Betradrivers. Nothing helps. Im realy frustratet. :(