OT maybe : Sony G420 monitor problem

  I have a sony G420, running from a GF4 4400, and the problem is the
picture is not wide enough.  It's about a millimetre too short on both
sides.  In all resolutions.  Picture width is at 100 in the sony menu, can't
go any higher.

  Is there something wrong with the monitor, or is the video card making too
much overscan ?

  Picture centering is at around 50, I can easily move the picture off the
left and right side, picture height and centering is also in the 40-60
range, but with width I'm maxed out, and it hasn't even reached the edge.

 I would appreciate any ideas, or whether other people with this monitor
have similar issue.

 TIA.