Screen artifacts or Electric Snow


macrumors newbie
Original poster
May 22, 2011
Hello. I have a mid-2010 iMac that I upgraded to Mavericks the day it came out.

About a month ago I started noticing weird screen artifacts appearing randomly on the screen. The artifacts are basically patterns of asterixes that look an 8-bit electric snow screen saver:

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Beginning yesterday, my iMac started locking up and rebooting.

Anyone else have this issue?


macrumors 65816
Feb 16, 2013
Sounds like your computer could be dying.

Try installing Mountain Lion (or whatever OS you were using prior to experiencing the issue) and see if the issue persists. If it does persist then something is dying, probably your graphics card since screen artifacts are a common side effect of a graphics card nearing it's final days.


macrumors 601
Sep 15, 2006
New York City, NY
I agree with w0lf, sounds like the video card is about to go. You can try and open up the iMac to dust out the fan and heatsink and make sure the fan is working properly.
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