Walter Boyd wrote:

Thanks. That's a lot to digest but it will be interesting to see how it
shakes out...

Is your HDMI screen an exotic one, or a more
ordinary one ?

See if the box mentions native resolution value.

If the monitor has DL-DVI on it, I suppose that's
a hint it is an ordinary monitor.

An "extreme monitor" with a high native resolution,
might use only (two) HDMI or a DisplayPort.

The Wikipedia article on DVI, tells you how far single link
DVI goes, and how far dual link DVI goes. The "appearance"
of dual link, a full array of DVI pins, does not "guarantee"
the hardware is dual link. But if the Display control panel
has already shown 2560x1600 operation at 60Hz, there's a good
chance the DVI uses is DL-DVI.

The Wikipedia HDMI article has a table half way down
the page, that defines a few data points for HDMI operation.
Occasionally, a little interpolation is required, to work
out what other values might work.

For example, I see an entry like this. Maybe I own a
2560x1600 monitor at 60Hz. Will it work ?

2560 × 1440 75Hz 7.09 Gbit/s

I note that since the refresh rate I will be using is lower,
that gives more headroom on resolution.

1440 * 75/60 = 1600

which means 2560x1600 @ 60Hz refresh, would also be 7.09Gbit/sec.

Paul