The OS X 10.9.3 update caused graphic problems with many 2013 Mac Pros containing AMD D700 and D500 graphic cards, where after updating some video editing applications like Adobe Premiere Pro and DaVinci Resolve would hang or crash during the video export process, or exported videos would contain pink and green lines. This was also reported to happen with Adobe Media Encoder.
2013 Mac Pros with more than two displays also experienced problems after updating to OS X 10.9.3, where one or more displays stopped working.
Luckily the OS X 10.9.4 update has been confirmed to fix both 2013 Mac Pro problem. if you have a 2013 Mac Pro and are experiencing video export or multiple display problems, update to OS X 10.9.4.