SaX2 1280x1024@75Hz but Desktop 1152x864@75Hz only

Hi, I've just installed Suse 9.3 Pro on a somewhat old but working Intel PII server with an onboard Cirrus Logic GD5480 graphic chip. The monitor was configured with SaX2 and tested OK with VESA 1280x1024@75Hz and no 3D. However after rebooting and login to KDE or Gnome the desktop screen resolution is found set to the lower 1152x864@75Hz, and there is no higher resolution available to select. I verified again with YaST2 and the monitor should be set 1280x1024@75Hz. Why does this happends and is it possible to extend the desktop resolution? (On another newer PC, the desktop resolution is set 1280x1024@75Hz just like SaX2 configuration). Thanks, Terje J. Hanssen