This behaviour can appear on any model of Power Macintosh including the 7200, 7500, 8500 or 9500 series computers. It has also been known to occur on other Power Macintosh computers. For a particular model of monitor, one display may exhibit the issue while another display may not.
The behaviour depends upon a combination of conditions. The differences can be from a number of factors: CPU clock differences (video circuitry in different models can have different dot clocks and timing circuitry) or component variance (clocks, countdown cicuitry, also in circuitry the display). A display that exhibits this issue on one CPU may not exhibit the issue on another CPU.
The issue is cosmetic and no damage is occuring to the CPU or the display. There is no disruption in video sync and systems have stable video signals during the color depth transition.
The image bounce or flash on the display as the color depth is changed is normal for some display and CPU combinations. The display or CPU should not be replaced or serviced. Some combinations may show the effect, but it may not be present on all displays (for a certain model) or all CPUs.
Support Information Services