To overclock the ATI Radeon HD 5850 graphics card, we used the ATI Overdrive utility that is part of the CATALYST Control Center. When you ‘unlock’ the ATI Overdrive, you can manually set the clock and memory settings or let the ‘auto-tune’ utility set the frequencies for you.
Just for fun, we tried out the auto-tune feature to see if it could really find a stable clock configuration, and it worked in just a few minutes and did not lock up the system. This utility determines the highest core and memory clock frequency that is stable and shows you what the GPU temperature is and how much load the GPU is under during testing. We started out at the default settings of 725MHz on the core and 1000MHz on the memory, but was able to reach 775MHz on the core and 1125MHz on the GDDR5 memory. This is a 50MHz overclock on the core and a 125MHz boost on the GDDR5 memory ICs.
To test out the overclock we fired up 3DMark Vantage and manually set the fans at 100% just to be sure heat wasn’t an issue when benchmarking at this overclock.
The ATI Radeon HD 5850 Video Card Stock 725MHz/1000MHz:
The ATI Radeon HD 5850 Video Card Overclocked 775MHz/1125MHz:
Running 3DMark Vantage with the Extreme preset we got a score of X6657. The score went up X7110 3DMarks when overclocked, which was an improvement of 453 3DMarks or 6.8% with this mild overclock.