You may be having issues with hybrid shutdown, a feature that decreases boot time by loading important drivers and fragments of the kernel into a special hard drive page file before shutting down. This has the consequence of not stopping the CPU timer when you perform a regular shutdown, and sometimes the RAM usage remains.
To disable hybrid boot, type "Power Options" in Start and select Power Options (not Power and sleep settings). On the sidebar, select "Choose what the power buttons do." Click "Change settings that are currently unavailable." Under "Shutdown settings," uncheck the box next to “Turn on fast startup." Save changes, then reboot your PC and see if anything is different.