This week my 1070s were OC and followed How To Overclock New NVIDIA GPUs On Linux - Phoronix for one card with success.
Next I fit 2nd card, reboot and notice previous conf was modified and when I followed HOW TO - Install Coolbits on Ubuntu to control fan speed, xorg.conf is overwritten, so I tried the chattr hack and this then just spit out graphical error on login (tty’s work fine but need access to nvidia-settings GUI)?
create your own xorg.conf file as per this guide and you will be good to go…