Temperature, Power Consumption & Overclocking
To reiterate, in the current range of Radoen R9 GPUs, only the Radeon R9 290 series support the updated AMD PowerTune technology (also unofficially known as PowerTune 2.0). This newer version makes use of the card’s temperature, power consumption and voltage draw to determine how best to increase another attribute in order to maximize the hardware's performance. The default temperature target has been set at a high of 95 degrees Celsius, and fan noise is also considered as a factor for the new PowerTune feature. The rest of the series utilize more rudimentary PowerTune technology that's based on maximizing the available power budget to boost performance.
Unlike AMD, all the new NVIDIA cards support GPU Boost 2.0, which will boost the graphics core performance as long as it remains below a temperature and power threshold. The threshold has a default value of 80 degrees Celsius, and its value can be adjusted to further boost its performance. As a result, we can see the top three NVIDIA cards pushing at or near the 80 degrees Celsius mark. . The GTX 770 and GTX 760 cards ran slightly cooler at temperatures of 71 degrees Celsius and 65 degrees Celsius respectively since they are not top-end parts to put out a lot of heat. This also means the performance we've seen out of the NVIDIA cards can only get better if were to notch up the temperature threshold to match the AMD companions, but we pretty much like where they are now.
Though the default temperature for PowerTune is set at 95 degrees Celsius, the operating temperatures of the 290X and 290 hovered around below 90 degrees Celsius. This is where custom coolers of add-in card partners will come into play. On the other hand, it's also telling that the AMD GPU needs to pushed further in order to meet its rival's performance levels. One rank lower, we found the ASUS R9 280X card operated at a low 64 degrees Celsius. This is because the card features the proprietary DirectCU II cooling system. With the aid of its single fan cooling system, the PowerColor R9 270 card operated at just 62 degrees Celsius, a difference of 6 degrees Celsius when compared to the reference R9 270X. It also helped that the Powercolor card had a lower clock speed of 945MHz as compared to the recorded clock speed of 1050MHz of the R9 270X.
Another aspect that's not discussed as often is the tolerability of the reference cooler's fan. Across the board, we find NVIDIA's reference coolers markedly quieter than AMD's solutions. The after-market cooler options supplied by vendors in their custom edition cards improve this tremendously, but if someone were to opt for the cheaper reference models, then NVIDIA gets our nod. Most recently, we've made a note of this in our performance review of the top-end GeForce GTX 780 Ti over the AMD Radeon R9 290X.
With the R9 290, our total system power draw was at an unexpected low of 401W, under load, and the power consumption profile of the R9 290X is similar to the GTX 780. To reiterate, power draw is also one of the factors taken into consideration by both the AMD PowerTune 2.0 and NVIDIA GPU Boost 2.0 technologies in order to optimize the performance of the cards. The top-end GTX 780 Ti even has a new power balancing technology that appeared to be working well; with its winning performance levels, its highest power draw of 432W is lower than the GTX Titan. The power draw of the ASUS R9 280X also mirrors its direct competitor, the GTX 770. Naturally, the weakest cards in this lineup, the R9 270X and R9 270, had the two lowest system power draws under load.
During our overclocking exercise, we were able to push the pair of 270 cards to their overclocked states by the highest margins. In terms of best performance gains, it was the R9 270X that managed an average of 11.8%, with its GPU core operating at 1185MHz, a gain of roughly 13% over its recorded default speed of 1050MHz; while its memory modules were overclocked to 6500MHz, a gain of 8% over its default 6000MHz .
We had high expectations for the R9 290 pair as our previous experience with the R9 290X demonstrated its strong performance, especially against the older NVIDIA GeForce GTX 780 reference card. But it was the R9 290 that stole its thunder somewhat as it managed to garner an average overclocking performance gain of 9.6%, over the 9.3% gain of the R9 290X. The overclocked ASUS R9 280X also had similar performance gain in the range of 9- to 9.4%.
However, it was the green camp's NVIDIA GTX 780 Ti that stole the show has it garnered an average overclocking performance gain of 20%, more than half the performance margins of the R9 series. A good deal of this outcome can be attributed to the the GTX 780 Ti's new power balancing technology that allowed it to draw more juice from lesser used power rails and thus propel the card to greater heights.