Re: [gentoo-user] multiple monitor refresh rates and broken brains (was: fonts and bad eyes)

[Greg Turner]

On Sat, May 17, 2014 at 4:21 AM, David Haller <gentoo@×××××××.de> wrote:

> Oh, and _very_ importantly: get a _GOOD_ matt monitor if you haven't
> yet.
>

Apologies, David, for hijacking your really good question-thread, which I'm
also very eager to hear people's answers to.  But, this reminds me of
something I've been pondering lately...

I think maybe refresh-rate discrepancies are subtly evil in multi-monitor
setups.  When I look at my 59.9 kHz apple cinema next to my 60 kHz POS Dell
throwaway monitor, something spooky clearly happens in my brain -- if I get
up close and look carefully, the pixels seem to rather dramatically "swim"
near the bezels between the two monitors, in a way that reminds me of a
migraine prodrome (perhaps because, to some degree, that's exactly what I'm
inducing in my brain, by exposing it to high-frequency polyharmonic
interference (presumably, there's a >0.5 MHz harmonic between those two
displays, no wonder my brain doesn't like it!).

In practice, I don't seem to have had any huge problem from this (and I'm
going to get rid of that crappy Dell soon, anyhow) but I have heard reports
from people claiming this type of thing caused eye fatigue and headaches.

My semi-baseless theory is that, so long as the remainders of the greatest
common multiples of your various monitors' refresh-rates form nice clean
ratios like 1:2, 2:3, etc, you probably won't fry your wetware input
circuitry looking at them.

However, if, as above, there are ugly harmonics, I suspect it might be
pretty bad for some people.  If, like me, you're too cheap for the 100%
solution of buying identical monitors, maybe just try to ensure everything
you buy supports standard 60kHz standard modes, or even go read the
1990's-era ModeLine authoring FAQ's and attempt to actually understand the
problem and fix it, if you're feeling ambitious :)

Anyhow... we now return to our regularly schedule programming...

-gmt