Underclocking the GFX core to a minimum safe limit via the Intel® Extreme Tuning Utility™ yields neither a significant drop in power consumption or graphics capability. In a desktop use-case I would not suggest underclocking the CPU/GPU as our drivers (for desktop) are not designed with any power saving features in mind. It would be a wash as far as the negligible power saving vs. active desktop components are concerned.
I noticed ASUS motherboards have software that will adjust power levels to reduce CPU power: SMART DIGI+
I just didn't know how that would affect graphics. From your answer, it doesn't seem like it will work as I am envisioning.
Thanks for your help,