How do I test them one at a time? The only problem I've had was installing. Do you mean putting each in and running the installer and seeing if it quits? Or is there some easier way? Is there a test in OS X? > >> So - how do I figure out which one (both?) was bad? They were >> recognized by >> the system profiler and given a clean bill of health by Tech tool pro. >> Any >> advice would be most welcome. > > I can't see any other solution but to test them one at a time. Also, > check what is written on them, probably one of them has different > specs. Can't really tell what exactly to look for though :( >