2011 27" i Mac Video Problem

Hello,

I have a 2011 27" iMac that I have added an SSD drive to. The other night the screen went crazy, flashing all sorts of colors, etx. Eventually I was left with vertical pink lines on screen and not able to do anything. I tried restarting to no avail. Spoke with Apple and they said to bring it in!

I brought it to an apple authorized repair center, they tested it and replaced video card. Brought it home and three hours later it does the same thing again. The repair center siad it could be a combination with the logic card also. I shut it off for an hour and then bring it back up. Now it seems to be runnning with no problems three days later. I am wondering if I should have it looked at again.

Any ideas?

Thanks much,
Bill

 

iMac Video

Anyone care to pipe in? Looking for help here. Thanks. Bill