Same here. Black screen or reboot when using EVGA 970gtx SC.
No issues in other games except for Dragon Age. Setting the power limit to 95% fixes the issue. Not a PSU issue, tested with a new 600w. Reducing settings help but does not make it go away. For example playing in 1080p instead of 1440p, playing in high rather then ultra etc.
Best place to test and replicate this issue 100% of the time is at the The Fade quest. When in the fade there is a blocked passage that requires you to fight of emenies till the timer runs to zero.
Want to add that when running a 670gtx on the same computer, zero issues in 30 hours of game play.
