it's the AMD platforms where zero % core states are in play
When an individual core enters the low power C7 state, it is disconnected from the internal clock and it is disconnected from the voltage rail. That means the voltage for that core is reduced to 0 volts. All Core i CPUs built during the last 15 years do the same thing when they enter the core C7 state.
are capable of running not only AT the base clock speed, but WELL below it
You are right. All Intel CPUs can run at any speed they like. This includes the minimum speed, the maximum speed, the base frequency and any speed in between the minimum and the maximum. The point I was trying to make is that during normal use, the base frequency is just one of many speeds that an Intel CPU can run at. There is nothing special about the base frequency. The only time the base frequency is ever important is if you disable turbo boost. Then the CPU will be limited to a maximum speed equal to the base frequency.
Some people have a misconception that when they are sitting at the desktop and not doing anything that the CPU should be sitting at the base frequency. They think that turbo boost should only be used when they are actively working on something. That is not how Intel designed their CPUs to work.
Intel CPUs since the 6th Generation include a feature called Speed Shift Technology. When Speed Shift is enabled, the slightest load is enough to quickly increase the CPU up to its maximum turbo boost speed. A fast, responsive CPU completes background tasks quickly. This allows individual cores to spend a bigger percentage of time in the low power C7 state. Intel and Microsoft finally realized that locking a CPU to 800 MHz was not such a good idea.
Speed Shift Technology can change the CPU speed 1000 times per second. Popular monitoring software that is sampling the CPU speed once every second is not able to accurately track these rapid changes. Some monitoring software will over simplify things.
The average multiplier (FID) and average speed that each individual thread and core is running at is vastly different compared to the consistent 800 MHz number that HWiNFO reports for all cores. The reality is that none of the cores are locked to 800 MHz. Cores that are rapidly entering and exiting C7 can fool a lot of monitoring software.
Same problem happens when a CPU is power limit throttling.
HWiNFO reports that all cores are running at 5000 MHz while all of the individual threads are reporting that the CPU is averaging just under 2900 MHz.
At other times during the same power limit throttling situation, HWiNFO reports that 4 of the cores are running at 5000 MHz while the other 6 cores are all locked to 800 MHz. The average CPU speed is still the same as above, just under 2900 MHz.
Send me a message if you are interested in doing some CPU MHz testing. It would be interesting to see if all of your P cores really are locked to 5.2 GHz or 5.3 GHz. They should not be locked like this if you are using the Windows Balanced power plan and this plan is set to default settings.