I have a brand new computer (built yesterday) with an AMD Phenom II X4 965 on an ASUS M4A89GTD Pro motherboard. Today I noticed heavy vCore fluctuations: between 0.90V (idle) and ~1.30V (load). CPU-Z shows how my core multiplier goes from 4x (idle) to 17x (load). After doing some research, I discovered that the default Windows 7 "balanced" power plan sets the "Minimum processor state" setting to 5% by default. Having changed it to 100%, my multiplier now remains at a constant 17x, and my vCore appears to have stabilized around 1.27V.
My system temperatures are pretty good, with the processor idling at around 30°C, reaching ~45°C when playing demanding games.
My question is this: is there any reason to worry about these vCore fluctuations, seeing as they are apparently very closely tied to the operating system's management of the CPU core multiplier?
Edit: could it be Cool'n'Quiet working in the background? If so, are the multiplier and vCore differences normal?