I have an A500 modified to plus and A590 with 2m fast / scsi CF which has been very stable for the older (2012) set of slaves that I have.
I added a 1.5m ram/gary adapter and most games i've tried so far lock up. The adapter is a bit funky in that it connects to the middle pin of JP2, and the ram card has no extra wire needed with a 1mb agnus. It is wired and jumpered correctly.
http://i68.tinypic.com/24wxb9g.png
Does anyone know what might be going on here?