Re: 8400GS overscan/underscan adjustment missing
Nvidia added overscan compensation in 190.36:
Add a new OverscanCompensation NV-CONTROL attribute, available on GeForce 8 and higher. This option specifies the amount of overscan compensation to apply to the current mode. It is measured in raster pixels, i.e. pixels as specified in the current mode's backend timings.
Try the latest 190.42 driver. Also, NTSC only has 480 visible lines, so you might want to drop down to 640x480.