PastryChef... were you able to get the CPU frequency under 2 GHz when idle?
I'm not having much luck. I tried different configuration settings in Clover and tried generated SSDT.aml and SSDT-XCPM.aml. When I used ssdtPRGen to generate multiple SSDTs and decided to try SSDT-1.aml (not the SSDT.aml) which puts the idle frequency to 1 GHz. It did the same thing with OpenCore. Any idea why SSDT-1.aml is doing better job than SSDT.aml?
Update: I removed SSDT from OpenCore and now its showing near 1GHz idle speed. That's not the case with Clover as I enabled PluginType and it's showing higher frequency without SSDT. I guess Clover and OpenCore manages power management differently.