Thermal testing was conducted by monitoring idle and load GPU temperatures with the 64-Bit version of HWMonitor
. The idle condition was established by recording the temperature after letting the system sit for 30 minutes with only HWMonitor launched. The load condition was established by running 3DMark Vantage two times back-to-back, followed by two back-to-back sessions of the Resident Evil 5 benchmark. HWMonitor is able to log current, minimum, and maximum temperature, so when all testing was completed, the maximum temperature was recorded. All testing was completed on an open testbed with relatively still air in a room with an ambient temperature of 20C.
At idle we see that the HD6870 idles at about the same temperature as the HD5850, which is a good deal higher than the HD5870 on hand. But in all fairness, Sapphire did install a much higher performance on their HD5870, and it in turn runs much cooler than a reference card.
When it comes to load conditions, the HD6870 did get the hottest, but I would not necessarily call it hot. Many GPUs can run in to the 80 and 90 Celsius range, so hitting 78 isn't all that bad. Another thing to consider is that the HD6870 barely made any noise while hitting this temperature. While the HD5850 and HD5870 would ramp up to higher sound levels (sometimes mimicking a leaf blower), the HD6870 never got above a mild WHOOSH sound. Some adjustments could possibly be made to the fan speed controller in order to make it louder but to keep it cooler.