When using a NVIDIA video card under Linux, make sure Dithering = Disabled.
This may be set to Enable by default if the user is experiencing poor performance in Linux where Windows has no issue.
To disable dithering in Redhat/Fedora/CentOS using a recent build of the Nvidia Driver.
1. Open ““/etc/X11/xorg.conf”” and add the lines in Bold:
…
Section “Screen”
Identifier ...
Device ...
…
Option "FlatPanelProperties" " Dithering=Disabled"
…
EndSection
…
2. Save changes and Reboot.
****Note this can also be disabled in the Nvidia GUI****
Disabling dithering in Linux for an Nvidia graphics card being used in your host PC using Legacy Drivers.Note: You might need to modify the following steps depending on the changes to the latest graphics card driver. See the instructions from the graphics card vendor for details.2. Install the following packages
1. Install and upgrade CentOS on your PC/workstation
Note: The kernel version of the Linux OS being installed should completely match the Kernel Source Tree that needs to be installed. For example, if you installed CentOS 5.2 with kernel version 2.6.18-92.el5. When you install the Kernel Source Tree the only available Kernel Source Tree is version 2.6.18- 92.1.22.el5. This is a problem as the two kernel versions should be identical but are not. To resolve the matter, upgrade the OS to 2.6.18-92.1.22.el5 before installing the Kernel Source Tree.
The user must be "root".
Run “yum install $PackageName” where $PackageName is one of the following packages:
a. kernel-devel (Kernel Source. As mentioned above, the version of the Kernel Source Tree should completely match the version of the installed OS)
b. gcc –– GNU Compiler Collection
c. xmlto –– Package for converting XML files to various formats
d. python –– An interpreted, interactive, object-oriented programming language
e. ncurses-devel –– Development files for the ncurses library
3. Install the graphics card driver and modify the configuration file.
a. Get the graphics card information (Run “lspci ––v””)
b. Get the kernel information (Run “uname ––a””. x86_64 indicates 64-bitkernel, whereas i386/i486/i586/i686 indicates 32-bit kernel)
c. Download the graphics card driver from www.nvidia.com for your graphics card and OS.
d. Set the OS to run-level3 (no X11)
i. Open /etc/inittab
ii. Find the line that reads “id:5:initdefault:” or “id:3:initdefault:”
iii. If you have the first version, change the “5” to a “3” (id:3:initdefault:”)
iv. Save and close the file
e. Reboot your system, and then log in as root
f. Run the Nvidia installer that you downloaded (sh_path_to_installer)l. Let it perform all steps offered including steps to configure
g. Change /etc/inittab back to its original state (e.g., “id:5:initdefault:”) and save the file
h. Reboot your system
i. Ignore OS if it asks to configure the Nvidia card
j. Open Nvidia X Server Settings (Run ““nvidia-settings””) to change the display settings if needed. Press ““Apply”” and then ““Save to X Configure File
k. In some cases, dithering may be enabled by default, and it should be disabled if you are using this graphics card with PCoIP technology.
l. Open ““/etc/X11/xorg.conf”” and add the lines in Bold:
…
Section “Screen”
Identifier ...
Device ...
…
Option ““Dac8Bit”” ““False”
Option “RegistryDwords”” ““DitherAlgo8=3; DitherAlgo6=3”
…
EndSection
…
Note: Setting only the Dac8Bit option to TRUE disable dithering in some Linux distributions. However, including the second option turns off the dithering algorithm in most Linux distributions.
m. Save the file and reboot