corrupted fonts on a 1080p projection

[chaoliang]

Recently I tried to connect a ATI Mobility card with a Sanyo full HD projector via VGA. I found that only at certain resolutions the type faces are correctly shown on the screen (like 1024x768, 720p, 1400x1050 and so on). The type faces look terrible when the resolution of the projector is set at 1920x1080 and several other resolutions). Images seem not to be affected though. What can be the reasons for this behavior? Can true type faces only be optimal at certain resolutions? Or maybe it was the VGA input signal? I couldn't test DVI-HMDI since I didn't have the cable any longer.

The graphics card supports the HD resolution on the projector.

[gt40]

Have you tried turning off the "smooth edges of fonts" setting under the effects tab of screen settings?

[Marshmallowman]

What model projector is it?, LCD or DLP?
When you say true HD do you mean a full 1080p? or 1080i

You should try to stick with the native resolution of the projector and if you have to use other resolutions you have to deal with how well the projector scales/resizes it.
If you pick a resolution with the wrong aspect ratio everything will look wrong, in these cases you there should be some setting in the projector that could help, eg screen size, overscan..etc

As gt40 said you have various antialiasing/ font options to improve things.

[chaoliang]

I tried the antialiasing options but no luck.
The projector is full 1080p. I also tried the different screen modes.
Like I described in the first post, it only affects the fonts, not any images. The projector is not in Clone mode so theoretically the graphics card should send this resolution to the projector.