I decided to try install Sierra just so I can run with a working 'sleep function' and to compare with High Sierra, I have not done this step in High Sierra so it is new to me.
I am at this step:
Note: If you have an HP 6200/8200 with the i5-2400 you will need to use an ssdt.aml file to enable CPU power management.
Find one attached below. Place the .aml file into /EFI/CLOVER/ACPI/patched/ For the i5-2500 or i7-2600 CPU you should generate your own with Piker Alpha's script. See the guide:
Generate an SSDT. This will help enable speed stepping and CPU power management. Without it you won't get turbo boost or more than about three of the lower p-states, up to only about 2.2 GHz.
For a long while I could not figure out how to "place the .aml file into the said folder'.
After much googling and finally took a lead from step below:
install clover configurator and run it , mount EFI partition, as so on...
Now when I reach /EFI/CLOVER/ACPI/patched/ folder I saw an existing file SSDT-SB-i5.aml, what to do with it? Can the old file and a new SSDT.aml file coexist?