These instructions for installing an Nvidia card to use with IMOD may be helpful. They were updated in January 2017. The list of steps assume that you have already installed Linux with xorg-X11 and its associated drivers. Most of the commands need to be run logged in as root or prefixed with sudo. 1. You need to have an appropriate source and header packages corresponding to the kernel that you are running. On Fedora/RHEL systems these are kernel-devel and kernel-headers packages. You can install them with: yum install kernel-devel yum install kernel-headers or by installing the corresponding rpms from your distribution disk, e.g. rpm -ivh kernel-devel*.rpm kernel-headers*.rpm 2. Go to the Nvidia web site (http://www.nvidia.com) and go to the driver download page. Specify your card type and OS type and use Search to find the latest stable release drivers. Download the file, e.g. NVIDIA-Linux-x86_64-340.76.run. Notice links to the README file, which you may need to consult. After you have installed the drivers, this file is in /usr/share/doc/NVIDIA_GLX-1.0. 3. Switch the screen to console mode (Ctrl-Alt-F1) and log in, or ssh from another machine. Bring the machine to runlevel 3 with: init 3 4. Go to the location where you have placed your Nvidia install file and run it as recommended in the instructions, e.g. sh ./NVIDIA-Linux-x86_64-340.76.run Allow it to modify your xorg.conf for you. If the procedure fails, you will need to research the problems with your version of Linux. 5. Check your /etc/X11/xorg.conf. Make sure your driver line says "Driver nvidia". 6. Type startx and see what happens. Success is indicated by a Gnome or KDE desktop. Failure is a message saying the X server cannot come up. A frequent message is a complaint about no/missing screens. This really means that the nvidia driver could not start for one reason or another. You can examine the start up process in detail by looking in the file /var/log/Xorg.0.log. Make sure that the number of bits specified in the Display line matches up with one of the screens that is declared. 7. Log out of the session started with startx. Return to runlevel 5 with init 5 8. Log in as a normal user. Assuming IMOD is installed normally, run 3dmodv on the file obj7.mod (available in http://bio3d.colorado.edu/ftp/benchmarks/obj7.mod): 3dmodv obj7.mod Start the model spinning by typing Enter and 8 on the numeric keypad. After 5 seconds or more, type o to get an output of frames/second. You should probably get close to 60 FPS. If it is a lot slower than this, the Nvidia drivers and GL libraries may not be installed correctly. 9. Note that you need to reinstall the Nvidia drivers whenever either the kernel or X is updated to a new version. After the machine is rebooted and fails to start X, you just need to log in and enter, e.g., sudo /sbin/init 3 sudo sh ./NVIDIA-Linux-x86_64-340.76.run -as sudo /sbin/init 5