Usually, LCD panels do a decent job with auto-adjustment when they are connected to an analog video source. Imperfections in the process, though, result in ugly fonts and painful eyes over a period of time.
A good rule of thumb though is that the "busier" the contents of your screen is, the better the display will be able to auto-adjust. It can gain more information from fast-changing input than it can with, say, a huge blob of white text.
If you run Mac OSX and have X11 installed, you can however unleash the best tool I've ever found for running auto-adjust against. You can also do this under Linux (and perhaps most BSDs).
Here's how to do it with OSX with X11 installed:
- Start X11.
- Go into its preferences, and in the Output page, turn on "Enable the Enter Full Screen menu" option.
- Press Command+Option+A to enter full-screen mode.
- Close the xterm window that appears.
- You should now have a fine, repetetive black-and-white pattern on your display. You may see that it flickers or is distorted somehow. Now, press that auto-adjust button!
- Your screen should not flicker, and the pattern should now be uniform across the entire display, with no large artifacts or Moiré patterns. If your display still flickers and can't quite adjust all the way, it could be due to the video card, the cable to the display, or the display itself.
- Press Command+Control+A to leave full-screen mode. Notice how smooth all the fonts are, how straight all the edges are, and how your eyes feel so much better :)
Here's how to do it with something that uses x.org, like Ubuntu Linux, where you have administrator access:
Open a new terminal window.
Assuming your display is currently :0 and there are no other display numbers in use (this is typically true if you're the only one logged in), run this command in the terminal window:
sudo X :1
Press the auto-adjust button on your display.
When you're done, press Ctrl+Alt+Backspace to kill the X server on display :1. You will return back to your previous display.