This article explains the following two options at 640x480 resolution in the Monitors control panel:

* 640x480 NTSC-TV
* 640x480 NTSC

The reason the S-Video output to your monitor allows you two choices at the same resolution is because of convolution. The NTSC-TV selection provides convolution and the NTSC selection does not. Using the NTSC-TV option will provide a raster with substantially less jitter than with the NTSC option.

You can not see the menu bar because you are in the overscan mode. Select a reduced resolution (underscan mode) and you will see the menu bar.