According to FAQ for Intel® Turbo Boost Technology, the turbo frequency is the same for all active cores. Intel's 8th and 9th Gen Datasheet, Volume 1 (PDF) also mentions that:
All active processor IA cores share the same frequency and voltage. In a multi-core processor, the highest frequency P-state requested among all active IA cores is selected.
So, it seems like all active cores of an Intel x86 CPU are in the same P-state at any instance of time, i.e. they are running at the very same frequency.
However, different hardware monitoring tools (e.g. HWiNFO64, Rivatuner Statistics Server) quite often display a different picture with different cores apparently running at different frequencies. Is this due to the fact that such tools simply cannot pool frequencies at different cores simultaneously and thus displaying values obtained at different instances of time or modern x86 CPUs can in fact run different active cores at different frequencies at the same time?
P.S. I was able to find out that starting from Haswell-EP per core p-states (PCPS) are supported, but I'm specifically interested in ordinary desktop CPUs and not server/HEDT products.
