Poo. If I use your SSDT build, I get no PStates, lots of kernel errors on boot, and only turbos 29 thru 34 and a base of 12 all of which come from a place about which I am unaware. If I 'fix" the load errors by modifying the SSDT table build, everything is good except no speed stepping; I still get the ring table error but not the ACPI PState setting error; IOReg looks great but no Speed Stepping.
I am running as a Macmini6,2.
I have included both tests in the file; JOY being better (as in faster) than NOJOY (my changes; no kernel errors but no speed step) but neither actually function. Both files contain complete Darwin Dumper, IOReg, logs, DSDT, SSDTs as well as the original DELL SSDTs of which 5 of the 7 have to do with power management. SSDT-4 is related to the nVidia and SSDT-7 with fans, temperatures, etc. so you will see them loaded as my SSDT-1 and SSDT-2 right after the Apple PM table we are creating for this project as SSDT.
In any case, I am grateful for all of your efforts and hope that these files might lead to a better implementation for all. My system is a Dell 17R SE 3D, 16GB i7-3630QM with GT 650M.