subject: Use ATI Overdrive to Overclock Your Radeon Video Card [print this page] Use ATI Overdrive to Overclock Your Radeon Video Card
Using the ATI Overdrive feature of ATI's Catalyst Control Center, you can easily overclock your Radeon video card to squeeze out more performance for video games and other graphics-intensive applications. However, you need to be careful not to damage your video card by attempting too much overclocking at one time.
What is Overclocking?
Without getting too technical, overclocking is the process of exceeding the manufacturer's specifications by running a computer component at a higher clock rate. A standard clock rate is simply the number of cycles per second the manufacturer designed and set the component to run at.
Exceeding the manufacturer's specifications too far can damage computer components such as CPUs, video cards, and memory so experts agree that overclocking a little bit at a time until failure is the safest approach.
Every computer component is different, even ones that are technically specified to operate similarly. For example, two video cards may not be able to be overclocked at the same rate even if they are identical cards with the exact same specifications.
Typically, component manufacturers create video cards to exceed the maximum specified clock rates. This is done to provide some overhead or a buffer to ensure that the card operates within specifications. It is this overhead that overclockers tap into to make video cards exceed their specified clock rates.
Overclock a Radeon Video Card with ATI Overdrive
As part of the driver installation for a Radeon card, modern ATI video cards use the company's Catalyst Control Center (CCC) to control various aspects of a graphics card's features. Available only for Radeon video cards, the CCC also includes options to overclock the graphics card's core GPU and memory clock cycles. Part of the CCC, ATI Overdrive takes the guesswork and frustration out of overclocking your Radeon video card.
To use ATI Overdrive, begin by right clicking on a blank area of your Windows 7 desktop and selecting Catalyst Control Center from the menu.
Naturally, this opens up the Catalyst Control Center. To access ATI Overdrive, click on the Graphics button and select ATI Overdrive at the bottom of the menu.
You should now be looking at the ATI Overdrive options window. To begin using these options, you will first need to unlock them. Click on the picture of the padlock and confirm that you want to unlock the Overdrive features. Then, click on the option titled Enable ATI Overdrive.
Before you go any further, you should take note of a few things. First, notice that you can adjust the core clocks of the Graphical Processing Unit (GPU) and the memory separately by using the two sliders in the middle of the window.
Also notice that to the right of each slider, the application indicates the current settings. Our test computer indicates that current clock rates for the GPU is 725MHz and 1000MHz for the memory. Those are the factory settings for an ATI Radeon HD 5850. Your values will vary based on the ATI Radeon card installed in your computer.
To the right of each of the two sliders is a label indicating the maximum values for the GPU and memory clock settings. In the test computer used for this article, the maximum value for the GPU is 775MHz and 1125MHz for the memory. However, this does not mean you can simply move both sliders all the way to the right and get the maximum overclocking benefits.
Overclocking is a trial and error process; you move one of the sliders a bit to the right, click the Test Custom Clocks button and see the results. If the test fails, you must move one or both of the sliders to the left and try again. Continue until you can figure out the threshold for the GPU and memory clock values.
You can try clicking on the Auto-Tune button and allow the application to determine the right balance between GPU and memory clocks for you. Many people find that Auto-Tune tends to be a bit conservative. You can, however, use Auto-Tune to get started and continue your own experiments for the overclock values.
Under the two overclocking sliders, you can enable manual fan control. This control only affects the fan directly on the video card and not anywhere else in your computer. Although ATI's fan controls does a good job of automatically adjusting the fan speed to match the heat generated by a Radeon video card, you may wish to manually adjust the fan depending on the environment in which your computer is located.
If you make a mistake or want to set your video card to the default factory settings, you can click the Defaults button and all values will go back to normal. This is especially useful if you decide to stop overclocking your Radeon card and want to use factory default settings.
Note that once you unlock ATI Overdrive, you can't lock it again unless you uninstall and reinstall the drivers and the Catalyst Control Center. To use factory settings again, click the Defaults button and uncheck the Enable ATI Overdrive option.
Finally, you'll notice that at the bottom of the ATI Overdrive window, the application indicates the current values for both the GPU and memory clocks. Don't be alarmed if these values are much lower than factory specifications.
Some ATI cards automatically adjust these values when the card's full capacity isn't being used. This saves both wear and tear on the video card and allows the card to consume less power and generate less heat.
