To overclock the Sapphire Radeon HD 4890 OC graphics card, I used ATI Overdrive 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, I 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. I started out at the default settings of 900MHz on the core and 975MHz on the memory, but was able to reach 990MHz on the core and 1190MHz on the memory. This is a 90MHz overclock on the core and a 225MHz boost on the GDDR5 memory ICs.
To test out the overclock I fired up 3DMark Vantage again and this time got a score of X5451. The score went up 576 points, which was an improvement of 11.8%!
In case you forgot what the stock score was I tossed the overclocked numbers into the performance chart with the other cards to give you an idea on how it stacks up to the competition with the overclock. It is just a tad behind the NVIDIA GeForce GTX 275!
NVIDIA got the GeForce GTX 275 to us at the very last minute and we will be looking at overclocking on that card at a later time.