Cannot activate Sidecar

[Sebastien13]

Hello, First of all thank you for the participants of the forum.
By replacing my CG (GTX1060) to an RX580, I switched to Catalina 10.15.3.
The problem is that I cannot activate Sidecar.
I have a valid serial number and icloud works very well on my Hackintosh (iMac 14.2) and my iPad Pro 11 "(ipados 13).
I tried this command:
defaults write com.apple.sidecar.display AllowAllDevices -bool true;
defaults write com.apple.sidecar.display hasShownPref -bool true;
open /System/Library/PreferencePanes/Sidecar.prefPane
And I have a message :

Can you help me ?

 

[Jsalexjs]

Pretty sure that cpu and subsequent SMBIOS is simply too old.

 

[Ploddles]

What does that say in English?