If your forcing the CPU frequency to 99% with power plan it won't drop down into the lower power states.
Better to use the Windows balanced power plan and reset it to defaults to remove any changes you made. In BIOS P1 and P2 can be left alone and P0 Should be set to your maximum which I think you said was 4ghz.
Make sure your CPU settings in AI tweaker are set to auto so that they don't interfere with p-states. It's fine to use voltage offsets though.