Is there a fixed number of screen resolutions that X works with?

I just loaded NetBSD 1.3 onto my Centris 610 (with full 040, not LC).
When I "startx" in 640x480, things work ok.
But, if my screen is in 832x624, then the screen blanks out, I get the line
at the bottom of the screen that lists the monitor resolution and stuff,
then it just sits there.

I telnetted in from my other computer and it looks like everything is running.
(startx, xinitrc, X :0, twm, xclock, and 3 shells.)

Any ideas?  I'd really much rather use 832.624 on my 15" screen.

Thanks.
Roger

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     BadgerNet                         roger@badger1.net
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