ATI's Catalyst 3.8 Drivers: ATI Sanctioned Overclocking

There have been lots of questions about why we chose to do our Part 2 article using the 3.7 Cats from ATI rather than waiting until today to use the brand new 3.8 version of the drivers. Our reasoning behind this decision was two fold: we wanted to get yesterday's article out as a timely follow-up to last weeks Part 1 of the series, and we also wanted to do a comparison between the 3.7 Cats and the new drivers.

With the Radeon XT series, ATI introduced a new feature called OverDrive. The basic principle of OverDrive is that the GPU can run at higher clock speeds if it is running cool enough, so as long as the chip is cool enough it will safely overclock. ATI’s OverDrive technology uses a combination of a hardware thermal diode and software support to keep track of the temperature of the GPU. If the temperature is within certain predefined limits, the drivers will increase the GPU clock speed by a safe margin defined by ATI. Once the GPU heats up again to the point where ATI can’t guarantee no degradation of chip-life, the drivers will underclock the GPU to as low as its original clock speed (but never lower). The Catalyst 3.8 drivers enable support for the thermal diode present on the Radeon 9800XT and the Radeon 9600XT; note that none of the previous Radeon cards have the thermal diode and thus will not support OverDrive.

The whole idea that a reputable company would be building any kind of overclockability into their product has really intrigued us. We had lots of questions like: how much will performance improve, and will stability be an issue. How much can we really get for nothing? Well, the answers may surprise, but even if they don't, there are some very interesting implications from the way things have played out. But before we get to that, we are going to take a look at the new interface, and then go through all the games in the list one more time.

This time for our testing, we will only be doing 1600x1200 with AA/AF on and off for games that have the option. All of our graphs will use the data we collected for Part 2 and compare it to what we found after we received our drivers from ATI yesterday. It’s been a long night, but it was well worth it.

We used the same benchmarks on the same FX51 system as in Part 2. Let’s let the show begin...