“Before going further, the 7 watt figure for this system was before storage has been added.”
With the drives attached, idle jumped to 24-25 watts. A JMB585 SATA controller alone added 6-10 watts, and an ASM1166 in the wrong PCIe slot added 14 because the CPU fell to C2. The finished box sits at 15-16 watts. Any card in a CPU-attached slot blocks C8. Gadient only found that out with a Kill-A-Watt at the wall.