Thanks for the very interesting work... I just tried out the SSDT for RX580, and got the following results (before and after sleep)...
Before SSDT:
OpenCL:
View attachment 491769
Metal:
View attachment 491770
After SSDT:
OpenCL:
View attachment 491771
Metal:
View attachment 491772
So overall, a very mediocre increase in performance... but GPU die temp has come down anywhere from 5c to 10c, which is a real achievement!
Hope someone finds this info useful. PS. Using iMacPro1,1 SMBIOS
without agdpmod=pikera, Sapphire Pulse RX 580 8GB