Burn in on December 2012 iMac (27")
I have a December 2012 27" iMac with all of the upgrades to CPU and 3TB fusion drive. I swapped out the default 8GB ram with what was supposed to be compatible ram from Crucial. I am mentioning this in case it might make a difference in the problem below.
I have noticed a burn-in-like effect randomly on my screen. It seems to be most noticeable when I've been using the Mac for a little while, and I click the Applications folder in my dock, and the tile view appears with the dark grey background. On this background, when the problem is happening, you can see vertical stripes going across the grey area.
I haven't discovered the pattern of when it appears and goes away, but it seems like it appears after the computer is being used for a little while, and goes away if I stop using it for a while.
It doesn't behave like normal burn-in, so I'm thinking it could be: a software bug, or the video card, or the non-standard ram, or perhaps another issue related to the thin design? I can't tell if the striping is only happening in dark areas, or if it's just only visible in those areas, when it happens.
Anyone else seeing this?
I took a picture: