For a couple of years now I have had intermittent problems with my external monitor (Dell 22in connected with Thunderbolt->DVI cable).
Often a snowstorm appears on the external display, or the external display goes into sleep mode (turns off and the power button goes orange). Sometimes it recovers from sleep mode, restoring to either the snowstorm or correct display.
When this happens I generally have to unplug and reinsert the thunderbolt plug.
I've noticed it happens more frequently if I am watching a twitch.tv stream or running QuakeWorld client, so I'm guessing this is connected with the graphics chip overheating.
Sure enough, if I prop up the MacBook to allow air to circulate underneath, the frequency of these interruptions goes down.
I replaced the monitor and tried a different cable, but the problem persists.
I think this is a manufacturing defect. But I can't find any authoritative reference.
I would like to find such a reference so that I can feel sure that my next Apple laptop will be free from this vexation.
Can anyone shed some light?
PS how about an "intermittent" tag?