Not enough info to feel really confident, but here is what I found...
The xf86config file had all other resolutions commented out. I edited the
file to represent the display characteristic I wanted and then, viola,
everything worked beautifully. I know plenty of people who run Linux on AGP
i740 cards successfully. Keep hacking and you'll get it.
>I am a new user of redhat linux 5.2, I have a intel i740 display and setup
>as instruction which provide by redhat in ftp. I can display in 320*200
>resolution only (type startx to enter into X Windows), however I have
>1600*1024 resolution only when I enter X window by command "xdm". If who