Any of you any idea what is going on? I installed latest nvidia drivers and now CP is unplayable, going from 170fps down to 5fps every 3 seconds and than back up. Absolute unplayable.
Rebootet already 3 times no mods installed.

Unless a new driver solves a specific problem, there is no reason to update your graphics driver. You don't mention anything specific, so just try reinstalling your old Nvidia driver and do a clean install of it.

Whenever updating the GPU driver, it's a good habit to always do a clean install, and restart the PC afterwards, even if Windows doesn't tell you do it. Otherwise, remnants of driver files and registry settings can cause issues like this.