My mid-2010 15" MBP has been pretty dependable over the last six years. Last year I maxed out the RAM and put in an OWC SSD and now it feels like a new machine. Luckily I haven't had any graphics issues, but it has frozen a few times in the past year. It was running Snow Leopard up until a few days ago. Under SL it froze twice last year, both times while using FireFox. I had never had any problems with it up until that point. I finally got around to updating it last Friday to El Capitan. It froze once while running Safari and then today (after updating to 10.11.5) it froze when I woke it from sleep. I know there have been some freezing issues with El Capitan, but I almost wonder if it's something else since I had it freeze in a different OS as well. What could be causing this? Other than that issue, I've been loving El Capitan so far.