Many graphics controllers also allow users to increase their clock speed. A faster video display probably won't make a lot of difference on office applications or Internet browsing, but it could improve the quality of a high-performance game.
Overclocking a graphics card is easier than overclocking a CPU because it's done in software-either the control program supplied with your graphics card or a separate program such as RivaTuner (download from http://www.downloads.guru3d.com/download.php?id=13).
If your graphics controller has an NVIDIA processor that supports overclocking, the NVIDIA Display Control Panel is the logical choice. To change the controller's processor speed, follow these steps:
Open Device Manager (Control Panel System Hardware and click the Device Manager button).
In the Device Manager window, double-click Display adapters. The name of your graphics processor appears.
Download the latest version of the driver software for your graphics card from the NVIDIA Web site (http://www.nvidia.com/content/drivers/drivers.asp).
Install the driver software and reboot.
When the installation is complete, open the NVIDIA Display Control Panel. Click the arrow at the left side of the control panel to open the menu shown in Figure 18.2.
Figure 18.2: Choose the Clock Frequency Settings option to increase the graphics processor speed.
Look for the Clock Frequency Settings option. If your graphics controller supports overclocking, select the option to open the dialog box shown in Figure 18.3.
Figure 18.3: Use the clock frequency sliders to overclock your graphics controller.
Select the Manual overclocking option near the top of the dialog box.
Use the sliders to change the Core clock frequency and Memory clock frequency settings. Don't push the settings all the way to top speed. Try increasing the settings by about 10 percent of the original value.
Click the Test Changes button to let the program test your new settings. If the system works at the new settings, wait at least an hour to let the card heat up, and then try increasing them by another 10 percent at a time until the Test Changes routine fails.
When you reach the speed you want to use, turn on the Apply these settings option and restart the computer.
Chapter 10 includes more details about NVIDIA graphics controllers.
To increase the speed of an ATI card to what ATI considers an optimal level, use the Catalyst control program supplied with the card. From the Catalyst Control Center, choose ATI Overdrive, and turn on the Enable ATI Overdrive option. The ATI Overdrive function uses a sensor to monitor the temperature of the graphics processor, and automatically drops the clock speed if the processor overheats.
The RivaTuner utility also works with some ATI controllers, so it's worth a try. To use RivaTuner, use the Web site mentioned earlier and follow these steps:
Start the RivaTuner program. The dialog box shown in Figure 18.4 opens.
Figure 18.4: Use RivaTuner if your graphics card's control software does not support overclocking.
Under the Main tab, click the Customize option at the right side of the description of the video controller. A pop-up group of icons appears.
Choose the icon that looks like a video card, at the extreme left of the group of icons. The dialog box shown in Figure 18.5 appears.
Figure 18.5: The Low-level system tweaks dialog box includes overclocking controls.
Turn on the Enable low-level hardware overclocking option.
Set the Core clock and Memory clock sliders to the new values you want to use, and click the Test button at the bottom of the window.
If the new settings pass the test, turn on the Apply overclocking at Windows startup option. If they don't pass, use the sliders to reduce the speeds and test them again.
When you are happy with the settings, click OK to save your settings and close the window.
Click OK in the main RivaTuner window to close the program.
If RivaTuner doesn't support your ATI graphics controller, try another program called ATITool, as shown in Figure 18.6 (the version in the figure is a beta version, released for testing. By the time you read this, it will probably be the production version of the program). You can download ATITool from http://www.techpowerup.com/atitool/. Before you try to use the program, read the ATITool instruction manual at http://www.techpowerup.com/wiki/doku.php/atitool/start.
Figure 18.6: ATITool is a quick and easy tool for overclocking graphics controllers with ATI chipsets.