ATI graphics cards and the Catalyst Control Center software included with their drivers allow users to change the resolution of the system's monitor to several preset values. While the application has several preset resolutions available for display, the software may not allow certain resolutions even if the monitor supports their use. The available resolution values are stored in the system's registry; editing the entry for resolutions can add custom-sized resolutions to ATI's interface. The process uses the Registry Editor included with the Windows operating system.
Double click on the Catalyst Control Center icon in the task bar to open its interface. Click on "Information Center" and select the "2D Driver File Path" option. Note the string of letters immediately following the "Video\" folder. You will need this information to find the settings in the registry editor.
Click the Start menu and type "regedit" into the search box, then press "Enter" to open the registry editor. If the system runs Winodws XP, click the Start menu and select "Run." Enter "regedit" into the dialogue box and click "OK."
Click the small plus icons near the folders in the left frame to expand the "HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Video" folder. This folder may contain several folders labelled with large strings of alphanumeric characters. Expand the folder matching the string designated by the Catalyst Control Center, and then open the "0000" folder it contains.
Scroll down in the right frame to locate the "DALNonStandardModeBCD1" entry and double click on it. The Window that appears lists all the resolutions available on the system.
Create a new line at the bottom of the list containing the custom resolution values. Follow the format of the existing entries, using groups of two numbers separated by a space. The first four numbers represent the horizontal resolution, the next four the vertical. Following the resolution are four numbers representing the colour depth, and four for the refresh rate. Use "00 00" for colour and refresh rate to enable all standard values. For example, to create a custom resolution of 1440x900, enter "14 40 09 00 00 00 00 00" on a new line.
Click "OK" when finished to save the changes. Close the registry editor and restart the system. The custom resolution will not be available until the system restarts. After rebooting, change the resolution to the new custom values in the Catalyst Control Center or the "Display" section of the Control Panel.
The registry contains information critical to the system's operation. Do not modify or remove any extraneous information while using the registry editor, as unwanted changes may cause the system to malfunction or fail to start.