F17: Manual monitor adjustment required after each boot

Hi, since upgrading from F16 to F17, I have a weird problem with the monitor settings on my desktop machine. I'm using the nouveau driver. The controller is an Nvidia GeForce 7100 GS. The controller is somewhat older, it has one DVI and one VGA plug. Attached are two LCD monitors running a single desktop spread over both monitors. Running under F16, everything worked as expected. With F17, every time I boot the machine, the monitor attached to the VGA plug is wrongly adjusted, but always in a different way. Sometimes it's just a bit off and text on the screen is flickering. Sometimes the entire picture is too wide, sometimes it's off to the right, or to the bottom, etc. Either way, every morning I now have to press the magic key sequence on the monitor to readjust the picture. Did anybody encounter the same problem? Does anybody know how to fix this, perhaps? Thanks, Corinna