Install NVIDIA (non-free) on Manjaro

Install NVIDIA Drivers

sudo mhwd -a pci nonfree 0300

Configure The Resolution/Refresh Rate

sudo nvidia-settings

Save to X Configuration File button and save to /etc/X11/mhwd.d/nvidia.conf

sudo mhwd-gpu --setmod nvidia --setxorg /etc/X11/mhwd.d/nvidia.conf

Configure X Screen settings (OpenGL Settings, Antialiasing, X Server XVideo)

Troubleshooting: X-Server Failed to Start and Install

sudo mhwd -r pci video-nvidia    

Reboot your computer

sudo gedit /etc/mkinitcpio.conf 

delete the word nouveau from the following line:

MODULES=" nouveau" 
# sudo mkinitcpio -p [linux kernel version]
sudo mkinitcpio -p linux419
sudo mhwd -a pci nonfree 0300