X51 R2 - GTX 960 constantly causing black screen and reboots?

I've been dealing with my X51 R2 problem for a little over a year now. My temporary solution was to simply use the default HDMI output that isn't connected to the video card, but I'm upgrading to a 4k monitor and would like the video card it for gaming. Here is exactly what happens... when using the GTX 960, the desktop will turn on and run for a couple of minutes smoothly, but the fans will speed up rapidly at some point and cause the screen to go black with "no video input" and then either gains signal or the whole system will restart. I have literally tried everything I can think of, which is why I'm posting on this forum.

Things I have tried...
Every video output from the GTX
Updating Alienware BIOS to A12
Updating all videocard drivers
swapping hdmi cables

I recently downloaded MSI Afterburner to monitor the card. The temperature seems to be fine, but the GPU Clock speed sits at 135MHz and Mem Clock sits at 405MHz (both idle), but right before the system will reboot, they jump to well over 1000MHz and 3000MHz.  I've read every forum and I know this is SUCH a common problem with the X51 R2 but nothing is helping. All suggestions appreciated!!