It could be an optical illusion. I have heard of such an effect, but
don't recall the specifics. Apparently easily reproducible if you know how.

Franklin wrote:

My monitor's display seems to twitch slightly every ten minutes or
thereabouts.

It's just a very small movement but I notice it easily when I am
reading the screen. The movement seems to be mostly in the
horizontal plane. It never used to do this.

As best as one can guess, is this likely to be a fault with the
monitor or with the graphics card?

The monitor is a 17 inch CRT and the graphics card is an NVidia
GeForce2. Both are about 3 years old and have worked faultlessly up
to now.

My mains power supply seems fine. I recently removed several devices
from my PC (three hard drives) so PSU is more lightly loaded than it
has been.



--
Joe Leikhim K4SAT
"The RFI-EMI-GUY"

The Lost Deep Thoughts By: Jack Handey
Before a mad scientist goes mad, there's probably a time
when he's only partially mad. And this is the time when he's
going to throw his best parties.