Sometimes my Mac Mini, plugged to an LG IPS screen, display some Glitches. For example, times ago, in my Launchpad appears these glitches:
To solve these glitches I had to restart the Mac. Now in my Safari's Top Sites there's this:
(all these glitches were immortalised with screenshots).
However sometimes, when I wake my Mac from sleep, all the screen appear with a green tint, in that case, taking a screenshot, it appear without issues and, to solve the issue, is enough just put the Mac in sleep than wake it up again.
I can't understand the cause, Apple's Genius says that, for him, is the HDMI cable, my scare is that the trouble is the GPU because my AppleCare will expire soon... For you where is the problem? Are there some test to do?