On Thursday, July 17, 2014 4:01:32 AM UTC-7, N_Cook wrote:
Feeding to an external monitor with 1600x1200, the image is locked but
feeding a colour bar test signal in...
Left side white to mid of the RGB colour bands are saturated full on RGB
colour and to the right of centre all are black.

Another way to see the monitor speeds is to use the menu on the monitor (some
monitors, anyhow).
It's possible that your saturation-or-monochrome issue is related to the
memory limits of the video (card?) - sometimes there are just not enough
memory bits available to have both highest resolution and 24 bits of
color information for each pixel. If it's really 'black', though, that's more likely
a gamma setting or (old monitors) analog gain and offsets of the
R,G, and B , as well as the (CRT) "screen" brightness control. The
gray-bars test pattern is required for making these adjustments, as well
as some HV precautions and insulated adjustment tools.