So after updating to Mavericks. My 1 year old rMBP now starts to completely freeze after 5+ hours of use. I used to use the rMBP for way more than that with no problem at all, daily. Programs I always have on are iTunes 11, Mozilla Firefox, I use others too on and off. It just froze so I had to force shut down, and turn it back on again. Happened to me yesterday TWICE. Any tips on whats going on?