We can set up three kinds of overclocking: increasing the clock at which the video processor runs, increasing the clock the video processor uses to communicate with the video memory, and increasing the clock the motherboard uses to communicate with the video card. You can even perform these three options simultaneously in order to explore the maximum performance your video card is able to provide. The first two overclockings are accomplished by configuring the video card; you can change these two clocks on any video card. The third one is done on the motherboard setup and will depend upon whether your motherboard provides this configuration option or not.
The first thing you need to do is to discover the core clock and the memory clock that your video card is currently using. The best way to check this is by using a program called PowerStrip. This is also the program we will use to overclock the video card. Depending on the version of the video driver you are using, it can provide the same functionalities as PowerStrip – including overclocking. Since we cannot be certain that your video driver has this feature, we prefer to use PowerStrip.
Upon running this software for the first time, you will immediately see the clocks your video card is using. After the first time, PowerStrip will start minimized on System Tray. You will need to right click on its icon and choose Performance Profiles, Configure.
Be aware that for ATI-based video cards, PowerStrip will report the real memory clock; for NVIDIA-based video cards, it will report the DDR clock (real clock x 2).
Let’s look at two examples. In Figure 2, you can see the clocks used by our Radeon 9800 Pro: 378 MHz for the video processor (“core clock”) and 337 MHz for memory. In Figure 3, you can see the clocks used by our GeForce 6800 GS: 425 MHz core and 1,000 MHz DDR memory.
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Figure 2: Clocks used by a Radeon 9800 Pro
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Figure 3: Clocks used by a GeForce 6800 GS
You can compare the clocks your video card uses with the manufacturer’s default clock for your video card. Click here to take a look at our “ATI Chips Comparison Table” or click here to take a look at our “NVIDIA Chips Comparison Table.” Please notice that the memory clock rates on these two tables are “doubled” (i.e., DDR).
As you can see in our table, Radeon 9800 Pro has default clocks of 380 MHz for core and 680 MHz DDR (340 MHz x 2) for memory. GeForce 6800 GS has default clocks of 425 MHz for core and 1,000 MHz DDR (500 MHz x 2) for memory. Our two video cards were using the default clock rates set by the chip manufacturer. Small differences below 5 MHz are normal, which means that your video card is not running at a “wrong” clock rate.
Sometimes you will find that your video card is factory-overclocked, meaning that the manufacturer has already set it to run at a higher clock rate. Even if this is your case, you can try to overclock your video card even further.