Look at Intel P-state driver from linux kernel

[eskin]

With option no_turbo it works great!
And Speed Step is working.
https://github.com/torvalds/linux/blob/master/drivers/cpufreq/intel_pstate.c

[eskin]

More info

Try this:
read_msr( core, MSR_IA32_PERF_CTL, &val );
// Set bit 32 to 1.
val |= ((uint64_t)1) << 32;
write_msr( core, MSR_IA32_PERF_CTL, val );

Source:
https://github.com/pyrovski/powertools/blob/master/msr_turbo.c

[nanoant]

Could you please elaborate what is the benefit of this change?

[eskin]

I didn't test this on mac, yet, but in linux with "Intel P-state driver" you can disable turbo without disable Speed Step.
So, my macbook CPU is overheat when all 4 cores load at 100% long time. After that the CPU is periodically throttling.
If i disable turbo boost, but not disable Speed Step, my macbook will be cold and silent and battery long time working.
That is the goal.