Black screen while sound and programs are running

[athinamj]

I have a new iMac 27'' late 2013 which I purchased almost 2 months ago.
Today I experienced a problem I haven't come across before. While the iMac was idle with programs running and sound it tried to get to sleep or screen saver mode and the screen went black with the 4 four edges of the computer white. I wasn't able to bring it back by using the keyboard and the mouse so I pressed the power button and restarted. My keyboard and mouse are both Logitech just to inform. I have Mavericks fully updated. How can I fix this issue and what might be causing it?

 

[h9826790]

The same thing still happen after restart?

 

[athinamj]

No, it didn't happen but I will keep monitoring it!

 

[zeropointzero]

I have same issue. Late 2013 BTO iMac 27" 1tb sad, 32 GB ram, i7, and 780m video card. What I noticed, surfing internet, 1 or 2 programs running in back ground. I walk away or don't touch keyboard or touchpad for a few minutes. Screen dims ( normal) then goes totally black. I touch keyboard to "wake" system, screen wakes up black with backlight lit. I keep tapping keys and running fingers over touchpad, after a several seconds the web page images might reappear or I have to do a hard reset.

All Mac software is up to date and I am not running any boot camp crap. Totally stock Mac software and stock iMac keyboard, touchpad. This happens every time I try to wake the system when the screen has just gone totally black.

 

[h9826790]

Disable the screen saver may solve the problem.