4 GPU runs more or less stable with latest beta7 of 12.11. Only sometimes very rarely the complete desktop freezes at that point where all 4 GPU simultaneous write the data back to host. Linux is no option for me at moment because it is part of a commercial software which is Windows based. The only thing I can do is change the vendor, but means from bad to worse. May be I will make a try with Linux later.
We're also somewhat restricted to Windows for commercial reasons but if Linux is dramatically better i.e. works with 8 as opposed to 4 then we may have ground to ask specific teams to consider migrating to Linux. I'll try the beta next time I'm on windows but the last time (still with 12.11 beta) I couldn't even work on windows due to serious instability. Oddly the beta seems perfectly stable on Linux. We will also try vendor alternatives and see if 8 can be reached on windows.