Photonico
Always through eopkg, never through the nvidia website.
As already stated use the application "Hardware Drivers" in the system menu and it takes the guess work out of choosing the correct driver as Solus supports multiple nvidia driver branches and multiple kernels. Choose the wrong combination and you'll boot to a blank screen.
I know however your card will support this driver and unless you've changed your kernel to the LTS kernel this will work (You would know if you switched):
sudo eopkg it nvidia-glx-driver-current nvidia-glx-driver-32bit
The 32bit driver package is needed for steam / gaming.
Be sure to do a full system update first if you have not already.
sudo eopkg up -y
