Idle clock speed is supposed to be 4.7 ghz without C-states if turbo boost ratios for each core loads are not set separately. 4.7 ghz is the 8 core turbo boost load speed. If default turbo boost ratios are enabled, it will boost to 5 ghz on 1 and 2 core loads.
If it was idling at 4.3 ghz, then the turbo multipliers were not set properly. 4.3 ghz is the default cache ratio. 3.6 ghz is the "base" clocks (if turbo boost were disabled without multiplier override).