I've had this issue since the patch too. As soon as I logged in, I got 2-10 fps at best in a house while doing nothing. After doing all the checks I could possibly think of (including a nice vacuuming..just in case), what seemed to work for me was just to re-log until magically the game started properly.

Will try the thing with the config file, cuz this happened 3 times now (basically whenever I log in for the 1st time in a day). Thought the maintenance yesterday would fix it, but no.