With the launch of the AMD Radeon HD 5870 graphics card fresh on our minds, we couldn’t help but wonder how far we could overclock the card if we weren’t limited by what Catalyst Control Center capped us at? With stock speeds of 850MHz GPU and 1200MHz Memory, there may be a bit of extra headroom to overclock this beast!
Armed with RivaTuner, we were let down…the latest version that we could find did not support the 5870. With no support in either RivaTuner or ATI Tool, we decided to talk to the man who has already pushed the card to the extreme, Sami Makkinen.
Sami pointed us at a tool that would let us have free reign of the GPU and memory clock speeds, the AMD GPU Clock Tool. The 1.82MB tool is a free to download as well. After a brief install we were quickly able to get hold of the might Radeon HD 5870’s clock speed.
You can see here that we can also monitor things like temperature, voltage, and fan speed with this utility. It’s quite handy in that you can set the polling interval as well.
Wasting no time, we started ratcheting up both the GPU and memory speed. At default voltage, we were able to reach a maximum stable overclock of 935MHz GPU and 1280MHz Memory. This is a gain of 85MHz and 80MHz respectively. We were able to get the card to run at 950MHz but would lock up midway through the second 3D Mark Vantage test. With a little more voltage 950-1000MHz should not be a problem on the Radeon HD 5870.
Unfortunately, setting the voltage wasn’t something we could find with this utility. With a current max of 1.15v there appears to be room to go up! Another problem that we encountered was that ATI Overdrive did not like settings changed outside of itself. We tried to run the fan manually but as soon as you change clock speeds with the GPU Clock Tool, the fan would reset back to auto control.
You can see in the two pictures above that the AOD utility is not happy when using the AMD GPU Clock Tool.