The driver CD includes the user manual, drivers and ASUS utilities, presenting them in an attractive bubbly user interface. The latest 11.2a drivers can be downloaded here.


The ASUS SmartDoctor tool is an overclocking utility that has the unique capability of allowing users to increase the GPU core voltage. The user interface isn't as sophisticated as MSI's Afterburner application but keeping it simple is not always a disadvantage. At the bottom are three slider bars where users can select the VCore and clock speeds. The maximum limit for the voltage is 1.5V while the clock speed is limited to 1780/11000MHz (limited is probably not the right word…), plenty of headroom for this card. On the main screen, the application displays the temperature or selecting the fan tab will show you the fan speed. Going into the settings, it's possible to create a fan profile based on temperatures.


Here, we can see how easy it is to overclock. Simply use the sliders to set the desired clocks and it's good to go. Of course, this doesn't imply that all clock speeds will work and users will still have to go through the usual steps of testing for stability.


The latest drivers bundles the new Catalyst Control Centre interface which is on the whole a more intuitive experience. Each section to the right has been neatly arranged for users to customise a range of options. The overdrive tab is largely unchanged in functionality. Overdrive gives uses the ability to overclock their graphics card and monitor temperatures and fan speed. Although not as thorough as MSI Afterburner, it is still a very useful tool. The new feature, shown above as Power Control Settings, is AMD PowerTune.

AMD PowerTune

Overclocking is nothing without stability and for most enthusiasts; applications such as Furmark, OCCT or MSI Kombustor have been the stress test of choice to truly load graphics cards. However, both AMD and Nvidia have voiced their concerns against the use of such applications due to the number of cards killed as a result of high temperatures and unforgiving load. They believe that stress tests are not representative of gaming loads and should therefore not be used as an indicator for stability.

This is where PowerTune comes in. The basic concept is that it locks the GPU’s thermal design power (TDP) to a pre-determined value such that when it is exceeded, the GPU will try to lower power usage. This is achieved by simply lowering the clock speed when the pre-determined TDP is attained under load. On the HD6950, the PowerTune Maximum Power is set to 200W whilst on the HD6970, it is set to 250W. AMD claim that typical gaming loads would draw 140W using the HD6950 and up to 200W using the HD6970, meaning that in typical scenarios, gamers shouldn't worry about their cards reaching the maximum TDP and throttling. The main situation where it PowerTune would kick in is under heavy loads from programs such as the stress test applications mentioned above. This particular HD6950 by ASUS most likely has its maximum TDP set to 250W to make better use of the power connectors on-board.

Overclocking presents another scenario where throttling might occur. Not surprisingly, overclocking will increase the power draw both in game and in stress tests closer to 200W/250W. This means that the card will be more susceptible to throttling as they exceed the PowerTune maximum TDP. AMD realise that PowerTune may not appeal overclockers but rather than giving them the option to disable the feature, they provide power control settings in Overdrive. Raising the limit to 20% sets the new maximum TDP to 240W on the HD6950 and 300W on the HD6970, still within ATX specifications. This gives overclockers additional headroom before throttling occurs. It also means that at stock clocks, the chance of getting reduced performance is much less. Conversely, to increase power efficiency, the power control settings can be reduced by 20%, making it ideal in situations where higher clock speeds are not needed.

In some ways, the system is akin to Turbo mode on both AMD and Intel CPUs. In the latter case, if power draw is within the TDP, the CPUs will have their speed boosted. Therefore, under light load, the CPUs will operate faster and simply clock to default speeds when the TDP is reached. In the HD69XX’s case, the core works at its default clocks and throttles when the TDP is reached. Nvidia have employed a similar feature on their GTX580/570 for the same reasons as AMD.

Throughout the benchmarks, the PowerTune limit was set at 20% to ensure overclocking headroom. However, at stock speeds, there was no noticeable performance difference between the 0 and 20% settings.