Do you have Raptr, nVidia Experience, or anything like MSI Afterburner installed that hooks into the video output? Having more than one of these programs running usually makes the video card run hotter and a lower frame rate than it should. Some of them (eg Raptr is installed with recent AMD drivers) hooks into every game by default, and other video capture software will have a fit if it's installed.

The only way I've ever been able to get FFXIV to crash is via video capture software.