To give a complete overview of the 6870 DirectCU we have taken readings from the card when it comes to temperatures, noise and power use.
For power readings the entire use of the system is measured and for noise levels we have the cards in a Corsair 600T case at floor level with our camera positioned by the case. Temperatures were recorded by GPUz and Furmark was used to provide 100% load on the card.
ASUS HD 6870 DirectCU
ASUS HD 6870 DirectCU OC
For power use the DirectCU version of the 6870 runs at a level which matches the reference cards. Even when we increase the core and memory speeds to their maximum available level there is only a minor increase in power use and the same can be said of the temperatures. In fact those are particularly impressive, sitting at 33-34°C when the card is idle and never rising above 81c at full load.
For acoustic performance on this card we were hugely impressed. As the video below shows the system is very quiet when in use. In fact the DirectCU is the quietest component in the system, our case fans and CPU cooler which are both running at low RPM are actually louder. This is a near silent GPU cooler.
One of the main features of the 6870 DirectCU is its ability to use the ASUS SmartDoctor software. SmartDoctor allows us to monitor aspects of the card and overclock it to enhance performance. The application also gives us the ability to tweak the GPU voltage which should increase the overclocking potential of the card.
From SmartDoctor version 5.74 onwards the 6870 DirectCU is supported and allows full control of the card provided we tick "Overclocking Range Enhancement" in the program options. From there it is just a case of setting the slider to the setting we want and hitting "Apply". Our only minor issue is that the messages given when changing voltages could be a little more user friendly. For example, trying to set 1.303v gives the following message:
Why not just say "Success" or "Set to 1.303V"?
So with the latest version of SmartDoctor installed and our card left to run at automatic fan speed we began raising the values past the standard Overdrive limit of 1000MHz core and 1250MHz memory. Our final maximum overclock was 1095MHz for the core and 1305MHz for memory with a voltage increase to just over 1.3v.
Here is how the card performed with the enhanced settings.