OK I did some testing again, but to no avail.
I tried turning on delayed transaction (was off), as well as playing with enable 15-16MB memory hole and some other undocumented stuff from the BIOS, but it brought me nothing. I also disabled ACPI and changed the video card and removed NIC, but the result was the same.
I removed AWE32, placed SB16 instead, changed ISA slots, tried different settings in autoexec.bat and config.sys, tried loading up only most basic drivers or none at all, tried loading up MK2 from windows instead of DOS, but apart from getting no picture - music still hang up the whole system in about 90 seconds.
Tried setting GM on port 300 instead of 330, but that's not default port and I get no music at all on that one in MK2 (cant be set up in the game itself).
I'm giving up - maybe in the next few days I'll test GM on my other rig - P1 133, Intel VX and Win95 and see what it comes out of there... So far, I'm at least pleased that GM works on Realms of Arcania 2: Star trail, if not on RoA 1: Blade of destiny. Do you know of any other affordable ISA (100% DOS compatible) sound card that runs Yamaha w/o hanging notes bug? How about Turtle beach Pinnacle?
P5A is revision 1.04, and yes - it does look like a twin of your K6 😁 Seems like you had absolutely the same idea as I did when u built up that system! With both 3dfx V5 and AWE32 w/GM. BTW I am also thinking about getting Promise RAID ATA100 controller and getting RAID-0 on this oldie. Imagine - FAT16, 2GB partition on RAID-0 😁