Hey there,

6bit + FRC is actually how many colors the panel can reproduce. Usually you see 6bit common panels with the ability to only produce 16.2milion colors which isn't enough for really accurate color reproduction. 8bit panels are much better at this job that could display more than 16.7milion colors. However, 8bit panels could be a little slower in the pixel response when compared to a 6bit panel.

So what the engineers did is to add dithering to a 6bit panel to 'add' or 'artificially' create more colors just like a 8bit panel. Of course it is still cannot be compared to a real 8bit panel but modern dithering techniques have come a long way so they are quite close but still have room for improvement.

So 6bit + FRC is something like a 6+2bit panel in which the first number 6 is the real specification while the second one is meant for dithering accuracy.