Video Card Overclocking - Heat

There are two main factors that keep the manufacture from running that card at the top speed. One is that not every card can run that fast. Each card has its own limits. This factor you can’t control.

The other factor is heat. The cards become hotter and hotter as the speed goes up. To keep the cards cool enough for use, the manufacturers limit the clock speed. This one you can control.

You can add additional after market cooling. Certain types of cooling will force the card to slow down if it becomes too hot to prevent damage to the card due to heat. I don’t really bother with temperatures until it starts affecting the performance like this.

I did see temperature greatly affecting performance with the 6800. While I sought the max overclock for the 6800 I experienced throttling. How did I know this was happening? My first hint came when the result from the first time I overclocked the video card was 90 FPS in the Counter Strike test. I bumped the speeds down a tab, and that is what I benched with. As you can see, it was fine from there, benching higher then the stock speeds. I was using the stock cooler on the card, and here are a few of the temperature readings I got. I used a program called rthdribl.

While it does heat up the GPU, it doesn’t heat it up to as high as the actual games. As you can see, the temperatures do get very high. I would highly recommend third party cooling. I would suggest Arctic Cooling, reviewed here by Kaoman, or if you have a water setup already, run it to the video card. Both of these will help cool the card better, and also may provide additional overclock.

Conclusion

Overclocking your video card will give you a nice boost in games and benchmarks. On most tests it was around 10 percent, but on some it was higher, and for Counter Strike on the ATI it was over 27 percent. Remember that no overclock is guaranteed. You could get a card that overclocks to double the stock speed, or you may get a card that won’t give you one MHz more. Chances are that you will be able to get a moderate overclock on the card.

Overclocking isn’t without a down side. As seen in the temperature readings from the 6800, these cards get hot fast. Heat not only makes the card unstable, but also can decrease the life span of the card. If you are going to overclock I would recommend third party cooling.