I've almost managed to get completely working system with Catalina on my Prime-A X299 and 5700 XT but I have this pesky USB stuttering / freezing issue. I first noticed it because I'm using a USB audio interface but it's also effecting other USB devices such as my mouse.
The problem is:
Let's say I output some audio through my USB interface and I decide to insert a USB thumb drive the audio stops for second. I've managed to figure out that it has to be a USB issue because if I try to move my mouse it also stops moving for a second as soon as I plug in the thumb drive. It doesn't matter where I plugin the thumb drive, front panel och back panel connectors, the issue persists.
I've tried:
With or without port limit patch
With or without USB-mapping kext (KGP-guide)
iMacPro1,1 and MacPro7,1 system definitions make no difference, I'm currently on a MacPro sysdef.
Removing all my SSDTs
I can't really figure out what my next move in troubleshooting is? Could It be a SSDT issue?
*edit* This is for me a completely new issue that I didn't experience in High Sierra. The only difference I made to my system was exchanging a 1080 ti to RX 5700 XT.