Yes, if you look at CPU-z, you can see your voltages fluctuate... the lower the voltage, the lower the temps. Load also effects temp... but in your situation especially with C&Q on, less load means less voltage.
Not all electricity that passes through the CPU is consumed. Though all electricity consumed is converted into heat. Bumping up voltage would increase the amount of electricity that passes through the CPU and since the CPU is a collection of transistors, electricity can't simply pass through as easily as standard copper wires and some electricity would be lost in the process.
"The downside was that the power-saving technologies ceased to work in idle mode. The CPU frequency would not go down when the CPU had nothing to do. As we found out, the power-saving technologies only work with 18.5x or lower multiplier. This is not a peculiarity of our mainboard or CPU. We can recall that we had the same thing with an AMD Phenom II X4 955 Black Edition in our earlier tests of Socket AM3 mainboards. It turns out that AMD Black Edition series processors do not have an unlocked frequency multiplier after all. You can increase the multiplier but the CPU only remains fully functional up to 18.5x multiplier, which may be not enough even for overclocking without any voltage increase. That’s very disappointing."