I had one of these in my Amiga 500: https://www.edsa.uk/blog/the-kcs-power-pc-board https://www.edsa.uk/blog/the-kcs-power-pc-board (this was before the PowerPC

I had one of these in my Amiga 500: https://www.edsa.uk/blog/the-kcs-power-pc-board https://www.edsa.uk/blog/the-kcs-power-pc-board (this was before the PowerPC CPUs appeared on the market, so the name wasn't as confusing as it sounds today). In addition to being a PC board, it also doubled as a memory expansion and RTC when you were using the host Amiga system.