Native Power Management

[mr-prez]

This is more of a recommendation and solution than an actual issue. I (and others from various threads) had the issue where during certain tasks, the CPU would power throttle down to 800Mhz even though temperatures were fine. It seemed to be tied to heavy IO tasks. I believe the solution to be letting MacOS natively manage power by disabling CFG lock.

CFG lock determines if the bios lets the OS directly control power management. Without it we can't boot unless we use KernelPM and/or KernelXCPM in Clover. This is actually a standard procedure mentioned in the OpenCore guide, but I stumbled upon it by searching GitHub for others hacking the 9750. I credit smallssnow for actually doing this with the 9750 and dreamwhite for providing a more general dell specific guide.

Long story short, we use modGRUBShell.efi to disable the 0x5BD offset which controls CFG Lock. Then remove KernelPM and/or KernelXCPM since we no longer need them. We can also use it to enable overclocking, disable DPTF (Dynamic Platform and Thermal Framework) etc. The latter was already disabled on mine so I only modified CFG lock.

I only did this yesterday, but I've since noticed better (quieter) fan control and haven't had the power throttling I did before. I also notice the processor scale between many more different clock speeds than before. I'm also currently running OpenCore, but I switch between Clover and OC since I do fresh installs every few months and figured it would be a good idea to mention this over here too.

In short, even if one doesn't particularly have the 800Mhz issue I did, it's probably a good idea to allow MacOS to natively control power management vs. emulate it.