Clock Rate And Temperature
The same challenges that faced us in trying to create a reference R9 280X for our power consumption testing also affect our frequency monitoring and thermal readings. Again, our U.S. and German offices received different partner boards with a variety of configurations. AMD, for some reason, pinned an embargo on those third-party products that expires later, so we’re setting aside measurements of the 280X for a round-up instead.
What we want to illustrate, though, are the effectively-achievable clock rates under load:
While the R9 280X that we adjusted to behave like a reference model can sustain the higher frequencies in real-world gaming conditions, the R7 260X and the R9 270X behave differently. We got the R7 260X to hit an almost-constant 1100 MHz by using the +20 setting in PowerTune, but saw little difference from the R9 270X. Tuning the card’s settings allows us to hit its peak clock rate more often, but that’s still not enough to call its ceiling a usable increase. This is why we’re using the R7 260X with its two PowerTune setups for our thermal measurements.
Temperatures Under Realistic Load
We took our thermal readings in a closed-up Corsair Obsidian 900D with its case fans spinning slowly and an ambient temperature of 22 degrees Celsius.
The R9 270X’s temperature rises and then levels off at around 80 degrees. In contrast, the R7 260X hits a peak value (with and without our PowerTune adjustment) and then backs off before stabilizing. These differences are the result of an evolved fan controller, which we’ll look at on the next page. Both reference cards seem to be designed for a maximum temperature of 80 degrees Celsius, though. By raising the PowerTune value, we’re able to push that boundary up.