Beige G3 RAM and PSU questions:

[Phipli]

Won’t it just recognise it as a 256MB module due to chip density?

The memory test works only up to 768 MiB installed. If you could add more (using two 512 MiB DIMM or one 1024 MiB DIMM) then it will crash. If the memory test is disabled (by setting NVRAM or patching the ROM), then it won't crash. This works in the DingusPPC emulator.

A 256 MiB SDRAM DIMM has 12 rows, 10 columns, 2 physical banks (bytes 3,4,5 of the SPD respectively). The theoretical 512 MiB or 1024 MiB SDRAM DIMMs would have 12 rows, 2 banks. The 512 MiB SDRAM DIMM would have 11 columns and the 1024 MiB DIMM would have 12 columns.

I don't think grackle can actually use more than 24 address bits per physical bank?

I haven't sat down and worked out if there is a combination that could work. But certainly configs work emulated. I was just curious if there was any which way it might work with 512. Not expecting it to work, but if I had one set up it wouldn't stop me turning off the memory test (hold down option or cmd+opt while launching the memory control panel) and shoving a stick in to see what happens. It's electrically compatible, so worst case it doesn't boot.

Edit - keep in mind that I'm not that savvy on RAM technology or specifics of the grackle.