I know this question gets way over asked and I am now guilty as charged. Anyway, I updated to El Capitain recently and I have had ZERO issues!! So now I'm asking the forever over asked question, - who is still using a 3.1 mac pro and likes it. Mine runs as well as its supposed to. I have refrained from going the SSD route in favor of putting that money aside for a new(er) computer. I figure I'll keep saving until the 3.1 isn't supported anymore, then buy as new as I can afford. For the time being its hang'n in there like a champ.