i've been doing some restructuring of my work setup, and I am now demoting the threadripper system, as i've now got a ryzen 9 3950x build on a brand new gigabyte b550 aorus master with 32gb of gskill tridentz rgb 3600mhz now in an older nzxt phantom 820 case. i'm passing down my radeon vii workstation card from the previous build until the next gen amd or nvidia cards come out. however the radeon vii is now giving me a lot of blackscreen problems when trying to play forza or have a lot of hardware accelerated apps running at once. this happened before in the threadripper system when i was using a single power cable with 2 8pins. i fixed the issue back then by using 2 separate power supply plugs. however now that tactic is no longer working, and i'm on the same seasonic 1200w gold rated power supply, so it cant be that. the motherboard is brand new and other than the blackscreen issues it's running great.
i'm on the latest drivers and bios. really not sure what to do. i can probably find november 2019 drivers that seemed to be the last before the blackscreen issues on vega7nm/navi started popping up, but that's only as a last resort for me. the build is in an older nzxt phantom 820 case with a 200mm side fan blowing directly into the gpu, so it's definitely not overheating.
I've tried various different driver versions and other suggestions from people on the linustechtips forums, and they have been a great help in coming up with new ideas; so far with their help i've tried disabling enhanced sync, going back to driver version 19.11.3 and using the 3 latest drivers, increasing power limits, setting the motherboard pcie slot mode to 3.0, swapping out my seasonic gold psu for a evga platinum one, and DDU'ing everything. all of these have netted me the same result; black screen and game crash a few minutes into any forza match. the system IS able to recover, but the driver is just highly unstable and other black screens do occur, but the system doesnt seem to fully restart, as it usually just brings me back to my desktop after about 30seconds.
none of this happened in my threadripper system (asus zenith extreme), only on the gigabute b550 aorus master that i just got. i am not experiencing any other issues with the board other than the radon vii black screens, so i dont believe it's that.