what display res can the xM support?

(i was chatting with r. nelson about this earlier but i figure i'll
just throw it out to the list.)

  what display resolution and refresh rate can my xM support? i have
a 1600x900 gateway:

http://support.gateway.com/s/MONITOR/2009/gateway/HX2000/HX2000sp2.shtml

with ubuntu 10.04.1. it displayed nicely at the original (prebuilt)
image res of 800x600, and still works with a dvimode value of
"1280x720MR-16@60". but trying for the full res of 1600x900 just
gives me "Frequency out of range."

  what's the limit on what the xM can drive? i assume it's based on
the pixclock value. based on a suggestion by robert, i tried to drop
the refresh rate but then got:

[ 2.761810] fbcvt: Refresh rate not CVT standard
[ 2.766510] fbcvt: 60Hz refresh rate advised for reduced blanking
[ 2.772674] fbcvt: 1600x900@24: CVT Name - Not a CVT standard - 1.440 Mega

i thought that was kind of strange since that seems to be coming from
the kernel source file drivers/video/fbcvt.c:

       if (!(cvt.refresh == 50 || cvt.refresh == 60 || cvt.refresh == 70 ||
              cvt.refresh == 85)) {
                printk(KERN_INFO "fbcvt: Refresh rate not CVT "
                       "standard\n");
                cvt.status = 1;
        }

but i thought i could specify a lower refresh rate.

  still catching up on all my xM stuff so i'm open to suggestions.

rday

p.s. i do have the xserver-xorg-video-omap3 package installed.