It is running 10 pro 64.
The video card is Nvidia GTX 750 Ti. (brand new)
The monitor is a Samsung UE590, connected with Display Port. (brand new)
Connected with a high quality display-port cable. (brand new)
RAM is 16 Gigs.

Everything looks great until the system is left idle for over one hour. Then, the display is corrupted. Lines through the video, colors are wrong, sometimes the screen is split into 4 panes with the video duplicated in each pane. Only a reboot will get it working again.

Ram test is good after 8 hours of testing.
SFC found no errors.
Nvidia drivers are updated.
Windows is updated.
I tried loading the video card using "FurMark", it ran the tests and everything was normal.

I do have a power plan that turns off the display after 1 hour. It does not sleep or hibernate.
Nothing noteworthy was in the event log.

What else should I look at?