Our overclocking tests basically consisted of us trying to reach the highest stable core and memory clock frequencies. In order to increase the frequencies, where possible we used ATI Overdrive in the ATI Catalyst driver control panel. For cards that did not allow access to the tool, we switched to using the manufacturer’s manufacturing tool, and, in the case there was no manufacturer overclocking tool, we used the freeware ATI Tool.

In our testing it ended up that all third party tools resulted in an immediate crash of the system, and so we were only able to use ATI Overdrive. The below graph is organized from the largest overclock to the least overclock.

The Sapphire X1650XT was able to reach the highest combination of a stable overclock and performance out of the three cards tested. Although the card did not have the highest core clock, the Sapphire video card’s memory was able to reach the highest frequency at 770MHz. Despite their difference in memory and core frequiencies, however, the overall performance of the cards ended up being very similar to each other.