It’s official – video cards on a MacPro have a life span of about a year.
A couple of days ago, my machine had another fit all to familiar : random crash with hyper-active fan turn on. A few days later, the issue happened again.
I didn’t waste much time in troubleshooting this time.
After a dusting and a disk utility (to be safe and repair corrupted permissions), I promptly ordered a new video card. Problem solved.