We are now able to find out what kind of power is being used by our test system and the associated graphics cards installed. Keep in mind; it tests the complete system (minus LCD monitor, which is plugged directly into an AC wall socket).
At both stock and overclocked speeds the ASRock P55DE3 shows us much more efficient power usage.
As a new measure, we are now monitoring the heat generation from the key components on the motherboard; this being the Northbridge, Southbridge (if it contains one) as well as the Mosfets around the CPU. The results are recorded at idle and load during the power consumption tests.
Unfortunately the small heatsink over the P55 chipset combined with the heat generated by the HD 5870 push the temperatures on the ASRock P55DE3 up.