new-jdm They definitely had FRC back then, just more primitive and in a more repetitive and noticeable pattern.
I have a samsung from 2008 where I can see it dither on grays while moving my head left to right (even connected to a dither-free old laptop).
I also have an even older NEC monitor, early-mid 2000s? And it dithers even harder regardless of what it's connected to, I can totally see it adding this repeating checkerboard pattern to all colors over and over again with just my eyes.
A lot of older monitors commonly used 6-bit+FRC to achieve 16 million colors.
However, in the 2000s, it was more likely these monitors were used without activating their dithering, because older OSes like Windows XP & 7 offered pure 6-bit / "thousands of colors" modes in display settings that were sometimes activated by default.
(This means in the 2000s, your monitor may have not been activating it's "dithering feature" yet if whatever old computer was used with it back then was only sending a pure 6-bit signal.)
However, newer versions of Windows and macOS only support 8-bit and higher — Windows does not list any 6-bit modes in List All Modes anymore starting in 2012 with Windows 8.
(With the reason why being that the DWM/"Aero" hardware-accelerated compositor — which is always-on in Windows 8 and later — only supports 16 million colors and higher. This is in contrast to Windows 7 and earlier which also offered a "Windows Basic" mode that would activate when running at lower color depths, and XP and earlier which did not include the DWM at all.)
This is one reason why even older monitors may be causing more strain than they "used to" back in the 2000s.
