So I just got a new haul of IIgs loot, and put my ROM3 board in a case.
I pulled the 8Mb RAMGS out of my ROM1 box and installed it in the ROM3. System became very unstable. Once had a "bad input queue" error (I don't remember the numerical code off the top of my head, but that's what google said it was), but the rest of the time it was screen garbage and lockups like you expect from bad memory.
Thing is, that card works fine in both of my ROM1 boards. I've also tried two Apple memory cards and an AE 2Mb card in the ROM3 board, and all of those work fine. It's just that RAMGS card that gives problems.
I also tried swapping power supplies, but that didn't help.
I don't see any incompatibility notes on their website, and their ebay listing says that it'll show up as a 7Mb card in a ROM3 machine (though I can't get far enough to see about that before the machine starts acting up).
What do y'all think is going on? My first thought was that it was shadowing some of that extra ROM3 system RAM, and they were both driving the bus at the same time and making things unstable. But after seeing that it's supposed to magically turn into a 7Mb card in a ROM3 box, I don't know what to think.