For what it's worth I get a very minor graphical corruption sometimes on the boot display (sometimes a few characters out), but it always runs fine.
I'm running my GG on an A1500 with an Apollo 2030@50MHz, 32MB RAM with Picasso II and Catweasel cards. The PC side has a 8-bit 3Com Etherlink II network card and a Soundblaster II 8-bit ISA card, with a 16bit Cirrus Logic-based 1Mb SVGA "Thunderbolt ISA".
You have tried disabling your CPU caches and stuff I presume...?