Recently bought a 7870 and there are yellow & pixels showing up, as such here:
And these are only showing up in games and some layering transparent items. Otherwise I never see them. It's hard to see but there are blue pixels in the image above, and there are yellow pixels where there should obviously be a dark box only.
They don't exactly move with it per say, but are dominant to the same spot. It just colors will show up better when moved over it. Like they're in a pattern, and it just shows up better.
Edit: Better example