I'm running an i3 desktop with an Nvidia GT440, using 1920x1080 and 1440x900 monitors. I booted up 13.04 64 bit and within 30 minutes I had three Unity crashes. On one occasion, everything was upside down and locked up. I was just using it and BAM - Chromium, Empathy, and Clementine - upside down. Then they locked up a few seconds later. Two hard reboots later (the first reboot brought me into single monitor mode with a seemingly horrible 640x480 esque resolution), I was back on. At this point I decided to install Nvidia drivers. I didn't want to install Nvidia drivers mostly because I wanted to give Nouveau a fair chance seeing as though some reviews indicated that Nouveau is pretty darn close to Nvidia these days in terms of performance. I installed Nvidia 313 + updates and things load much faster and operate more smoothly. I also noticed that the applications lens when scrolling through all applications is smoother as well.
With all of that being said, has anybody ran into any issues like this where your graphics with 13.04 and Nouveau just acts rather wild? I have a ton of faith in Nouveau and I'm sure bug fixes will come about. I just wanted to check in with other users to see what their current experiences were.