video refresh drops out-of-range at 40hertz?

I have two hardware platforms and one XPe build, I’m attempting to make one
ghost image interchangeable between the hardware platforms. The hardware
platforms are fairly close, accept for a different series of the Intel
graphics controller, AGP, IDE. I have it so that you can run the FBA on
either machine and create a ghost image to the other machine and all the
hardware is detected, but I’m having problems with the video controller. The
first time I boot the system after changing platforms, the video defaults to
640x480, 256colour, 40KHz frequency... which needless to say is out-of-sync
for both LCD displays the result is not pretty. If I shutdown windows
(blindly) and restart the system it seems to be bumped back up to 60Khz
800x600 256 colour. I then manually change the resolution back to 1024x768,
70khz, 16bit colour. btw i write an application based on some other comments
i read that would force the frequency back to 70khz, but it seems that
ChangeDisplaySettingsEx, dmDisplayFrequency doesn't seem to influence the
frequency setting at all.. still requires two reboots. Also this function
really seems to work only on VGA CRT monitors, as far as i can tell the same
application doesn’t seem to change anything on XPE at all. Any clue what
would cause it to drop to 40htz? or how to force it to stay at atleast 60htz?