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.

On Red Hat 7 at least, installation can fail with the message
   "Nouveau kernel driver is currently in use by your system"
The steps for dealing with this are:

  a) Make a file "/etc/modprobe.d/blacklist.conf" with the line
        blacklist nouveau

  b) Edit "/etc/default/grub" and add this to the GRUB_CMDLINE_LINUX:
    rd.driver.blacklist=nouveau nouveau.modeset=0 modprobe.blacklist=nouveau
     Then run
        grub2-mkconfig -o /boot/grub2/grub.cfg

  c) Start a bash shell if not running one and run
    mv /boot/initramfs-$(uname -r).img /boot/initramfs-$(uname -r)-nouveau.img
    dracut /boot/initramfs-$(uname -r).img $(uname -r)

  d) Reboot the system and try installing the drivers again

5. Check your /etc/X11/xorg.conf.  Make sure your driver line says "Driver
nvidia".

6a. If you are logged in to a screen in console mode, 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.

6b. If you are are doing this over ssh, return to runlevel 5 with
   init 5
and assess whether X is running with 
   ps -ael | grep X
If not, consult /var/log/Xorg.0.log.

7. Log out of a session started with startx.  Return to runlevel 5 with
  init 5

8. You can check whether the nvidia module is loaded with 
  lsmod | grep nvidia
This should give a line starting with nvidia

9. 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.
Note: You should get much faster rates with this model if you run
nvidia-settings, select "OpenGL Settings", and turn off "Sync to VBlank",
which limits the frame rate to 60.  For a better assessment of performance,
use the larger model ivem2578.mod from the benchmarks directory.

10. 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