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).
Power consumption on the ASRock P55 Extreme4 is good. It is not over the top like we expected (with the extra USB 3.0 and SATA 3.0 controllers to feed).
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.
Although it is not by much, the P55 Extreme does generate less heat than our other competitor.