You didn't say whether you have a problem to find the right timings so that the monitor recognises the resolution or if you have memory problems i.e. you cannot open test screens or something like that.
For the timings you could try my settings for a Mediator / Voodoo setup with a HP w2207h monitor:
Regarding memory, 1680 x 1050 means 1,764,000 pixels. With 8 bits (one byte) per pixel this would need 1.7 MB which should perfectly fit into the 4 MB of gfx memory. Even 16 bits per pixel (3.4 MB) could perhaps fit if you open only one screen and don't use a background picture.
If it does not work, you could decide to use a smaller 16:10 mode like 1280 x 800 or so.
Bye,
Thomas
