AMD 6600 on macOS: custom Zero RPM with softPowerPlayTable on DeviceProperties

[miliuco]

December 2023 Note

In this thread, SPPT string is taken to the OpenCore config.plist file.
I've added another option that most of the time works better: taking the SPPT string to an SSDT file.

Please visit the new thread, there you have the info that was here plus the new info added:
AMD 6600 on macOS: custom Zero RPM with softPowerPlayTable on SSDT

 

[Middleman]

Thanks for this Miliuco, this is very handy. I tried the above as you've recommended and found something strange. Using the GPU-Z on my Asus Z690 system it shows the RX6600 is using Bus 3. However when I run the MPT tool it shows two cards - a RX 6600 on bus 4 and a RX 6800 on bus 5. I only have a RX 6600 installed so I am not sure why is has that value there.

So I went ahead and selected the RX6600 card and managed to delete the SSPT (under bus 4) and load the rom as mentioned and uncheck the zero rpm boxes. But when I checked the registry editor, the PP_PhmSoftPowerPlayTable values came under 0004. There is however a 0003 which also contains the exact same info, but minus the PP_PhmSoftPowerPlayTable. I am wondering if I should manually copy over this PPT key to the 0003 to improve Windows performance (although I can see the 0004 folder seems to have a few more extra folder properties present such as DAL3_DATA and VolatileSettings).

 

[miliuco]

@Middleman
In theory, the registry key in which PP_PhmSoftPowerPlayTable is stored is the one that corresponds to the active GPU.
In my case, for example, PP_PhmSoftPowerPlayTable is stored in the key 003 and this matches the bus number shown by GPU-Z. There are also the keys 001 and 002 which are almost identical but do not have PP_PhmSoftPowerPlayTable.
I think that in your case the correct key is 004 since it is the one that stores PP_PhmSoftPowerPlayTable.
What I don't understand is why you see 2 GPUs when in fact you have only one or why GPU-Z and MPT show different bus numbers. For this I have no explanation.

 

[miliuco]

I have noticed that when I have the PP_PhmSoftPowerPlayTable key active, when I exit sleep from the screen or computer, monitor shows Input Not Supported and this message does not disappear until I restart.

This only happens if in System Preferences >> Screens the variable refresh rate (40-60 Hz) is selected, if I choose 60 Hz as fixed frequency the message is gone and everything seems to work fine.

 

[miliuco]

@RUSSKIYVOLK
Hey, write in English.
In theory, the registry key in which PP_PhmSoftPowerPlayTable is stored is the one that corresponds to the active GPU.
Click on Write SPPT and see where PP_PhmSoftPowerPlayTable is saved and get it from there.

 

[RUSSKIYVOLK]

Sorry for the Russian text, I didn't mean it.I did everything according to your instructions, only edited the text in the Windows environment .Everything is working fine so far, the extractors are spinning.By the way, I noticed that if you connect a video card to 4K to the monitor, the video card does not strain at all, the temperature is idle as in Windows

 

[miliuco]

@RUSSKIYVOLK
Yes, you can edit the text in Windows and go to macOS only for the final step in config.plist.
My fans are spinning all the time (almost inaudible noise) and temp varies between 30 and 35.
Stressing the GPU with benchmarks like Unigine Valley, the temperature can rise up to 80 but cools down in a very short time returning to low values.

 

[RUSSKIYVOLK]

@RUSSKIYVOLK
Yes, you can edit the text in Windows and go to macOS only for the final step in config.plist.
My fans are spinning all the time (almost inaudible noise) and temp varies between 30 and 35.
Stressing the GPU with benchmarks like Unigine Valley, the temperature can rise up to 80 but cools down in a very short time returning to low values.

what kind of monitor do you have?

 

[miliuco]

what kind of monitor do you have?

Lenovo 28" 4k. I'm working at 2560x1440.

 

[RUSSKIYVOLK]

Lenovo 28" 4k. I'm working at 2560x1440.

is there heating in 4k resolution too?