We also added that our own press card tends to drop its clock dramatically after some time of running and we recommend you to read our original part here. Just minutes ago we got an update from AMD that there is the AMD Catalyst 13.11 Beta9.2 driver that is supposed to fix the performance fluctuations in such situations.
AMD sent us the following statement:
"We’ve identified that there’s variability in fan speeds across AMD R9 290 series boards. This variability in fan speed translates into variability of the cooling capacity of the fan-sink. The flexibility of AMD PowerTune technology enables us to correct this variability in a driver update. This update will normalize the fan RPMs to the correct values. The correct target RPM values are 2200RPM for the AMD Radeon R9 290X ‘Quiet mode’, and 2650RPM for the R9 290. You can verify these in GPU-Z."
So basically AMD’s PowerTune technology is to blame, as it wasn’t setting the cooler at the right RPM speed. We will try to see if this new target speed for the cooler will get us more consistent scores as we found out that the card will result will serious reduction in performance after a few runs of the same test.
When it gets hot the card throttles down, resulting in lower scores. We have a feeling that this is not the end of it, but overall in Uber, noisy mode, the card doesn’t have these issues but it is noisy.
You can get AMD Catalyst 13.11 Beta9.2 driver here.