XFX Radeon HD 6850 Black Edition Video Card ReviewTue, Feb 22, 2011 - 12:00 AM
So now it’s time to see how far we can push this card before it gives out on us. I started out small going for an overclock of 850 MHz on the core and I left the memory at 1200. I had no problems, so I decided to push a little further and I took it up to 927 MHz but I dropped the memory down to 1100 MHz just to be safe. Again, I had no problems. So, then I decided to see if I could get over 1 GHz. As you can see from the screen shot below, I did. You will notice that I had already upgraded to the new 11.2 Catalyst driver before I decided to do the overclocking. I was able to reach 1010 MHz on the core and 1193 MHz on the memory with the voltage bumped up to 1.174 Volts. I tried the memory at 1200 but it wouldn’t do it even with a little more voltage.
For all of the overclocking I used the Sapphire Trixx utility because of its ability to change the core voltage of the GPU. The ability to do this gives us the advantage of higher clocks that just can’t be reached in the Catalyst Control Center.
I ran 3DMark 11 on its extreme preset once again to see what the difference would be with an overclock that was over the 1 GHz limit. As you can see there was quite a noticeable difference from its Black Edition setting of 820 MHz: a difference of 213 3DMarks, to be exact. To test the stability of the overclocks at each interval I ran the Furmark Benchmark at 1680×1050 resolution for one minute. If it crashed I threw it out, but if it passed I kept it.
With a higher performance overclock of 23% on the core and 8% on the memory came a thermal price to pay. Yes, I must say that the card does run hotter. At idle the temperature went up to 39C with the fan on auto speed and the during a full load test in Furmark it reached 67C in just a one minute test.