I used my laptop RAM (Samsung 4+2 GB DDR3) to upgrade my Mac Mini memory. At first boot I was able to work with no issue on the mac, but after I restarted the mac. It kept crashing until I put back the old ones. I'm pretty sure that the RAM I used was OK and functional. I have mid 2010 mac mini and current OS is 10.7.4 Yes it is kind of old. Does upgrading the OS help preventing from this matter? Thank you.