[mythtv-users] Does screen resolution significantly affect image quality on SD TV?

[Johnny]

I know the generic advice is to have your screen resolution match the
native resolution of your television. I am using component out on an
8400 GS with the HD480i setting to an SD TV. I have had my resolution
set to 640x480 but the resolution is cumbersome when I need to do
anything outside of mythtv (eg software updates, change a setting)
because most programs and dialog boxes don't fit on the screen. So I
have to constantly alt+click to drag the windows around constantly to
get to parts of the dialogue boxes. I have been running the display at
1024x768 but it seems like the image is slightly softer. I am not sure
what mythtv does when my screen resolution is at 1024x768 but my
output from the card is set to HD480i. Is it upscaling all of my
recordings to 1024x768 and then the card is outputting an analog
version of that? Or is the card downscaling it back to 640x480 because
it knows it is a 480i output? Or is it aware of the fact that the
video is 720x480 and the output is set to 480, so it does no scaling
regardless of the desktop resolution?

Also I am curious, if the image quality is decreased by using a higher
resolution, how do others feel about the trade off of having more
space on the desktop for windows vs the decreased image quality in
mythtv?

I am aware of and do have an Xvnc server running which allows me start
a session with a higher resolution for vnc connections, but I find
that I frequently want to quickly do something in the current session
that is on my TV rather than starting a 2nd session over vnc.