This moire pattern appears to be an interaction between the frequency of the dithering process being used to create the desktop color and the horizontal scanning frequency.
As you noticed, if you increase either the brightness or the contrast, the visibility of the pattern is reduced. Also, if you adjust the vertical size of the display, the pattern becomes harder to see.
Although this may be bothersome, it will not affect productivity nor is it indicative of an impending failure.
Article Change History:
17 Nov 1994 - Reviewed for technical accuracy.
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