The GTX 660 being a Kepler GPU should work fine with DSR. First thing I'd try is a driver reinstall after thorough removal. DDU works well in Safe Mode, and is very easy to use: http://www.guru3d.com/files-details/display-driver-uninstaller-download.html Then reinstall the drivers without all the nVidia bloat... since FS is the only "game" I use, I only install the driver itself.
HTH
Greg
HTH
Greg