Problem with 1680x1050 resolution with intel card

[Olive]

I have a problem with the intel driver and an external monitor
connected to the VGA port with the 1680x1050 resolution. The image is
completely garbled with strips along the screen. There are no error
messages and xorg and the external screen believes it works properly
(with the external screen detecting a 1680x1050 signal) (lower
resolutions work fine). This is not an hardware problem since
everything works fine on Windows XP. The problem appears with two
different computers. I give below the detailed information.

Olive

xorg-vide-intel 2.8.1 (but same problems with older version)
kernel 2.6.30-ARCH (archlinux distribution)
relevant part of lspci:

First computer (Ei-System 3089):
00:02.0 VGA compatible controller: Intel Corporation Mobile 945GM/GMS,
943/940GML Express Integrated Graphics Controller (rev 03)

00:02.1 Display controller: Intel Corporation Mobile 945GM/GMS/GME,
943/940GML Express Integrated Graphics Controller (rev 03)

Second computer (Asus eeepc 701):
00:02.0 VGA compatible controller: Intel Corporation Mobile
915GM/GMS/910GML Express Graphics Controller (rev 04)

00:02.1 Display controller: Intel Corporation Mobile 915GM/GMS/910GML
Express Graphics Controller (rev 04)