In my PowerBook, I had a 120GB IDE OWC SSD. OS X would kernel panic a lot, and the system would boot only to Open Firmware if the system was restarted, and the SSD vanished from the Open Firmware I2C tree. If I waited a few hours, it would work like normal for while, then crap out again. A hard disk always worked great on the same bus the SSD was on. I am sending the SSD back to OWC for RMA, but what would cause it to do this. This isn't much of an issue, as I have a backup MacBook Pro, and the PowerBook is currently getting a new CPU soldered in, so it wouldn't work anyway, but I just wonder what caused the issue.
I would think heat or a power issue somewhere in the system