What controls Turbo Core in Xeons?

[SPBHM]

As up to date, I think everyone already knows Turbo Boost Unlock doesn't work on v4 family. In my case, what I haven't understood yet is why.
Does anyone has a technical explanation for that, or a link to any good details for me to understand the reasons?
Thanks

I think this unlock relies on old microcodes that are not supported by Broadwell only by Haswell CPUs,
also I know that this turbo unlock trick also works o lga 1150 with locked Haswell CPUs, it's very nice for some low power models like the e3 1260l or or something it goes from around 3GHz to 3.7 in full load

 

[maxx7650]

I managed to Unlock the turbo in Windows now the question is how do I undervolt it? how can I inject the V3_payne_70_50.efi?