My comp's been restarting at random times, and when it comes back the SSD drive can't be found by the BIOS and it doesn't boot. Powering down and starting up again fixes it 90% of the time, with a second reboot occasionally required.
Does not seem to be heat related; it's never happened with me actually on the computer. It has happened while acting as the squeezebox server, however.
It's a Sandy-Bridge i7 arch if that helps.
To add: I've also run Windows Memtest and it came back with no issues.