System is Lenovo 9964-A7U with Intel Q45 graphics running Windows XP.
Monitors are both 17" Acer V173 with native resolution of 1280x1024. Both use VGA connectors. Secondary monitor is connected using Display Port to VGA adapter.
In windows display properties, I can set both monitors to 1280x1024, but only monitor 1 (connected directly using onboard VGA connector) actually displays this native resolution. Monitor 2 (connected to DP using DP-to-VGA adapter) is actually sent 1024x768 with "scrolling" to allow the viewing of the parts of the 1280x1024 picture being sent.
I have installed the monitor drivers and Display Properties shows correct resolution for both monitors and appears to think everything is OK.
I have also installed the latest drivers from Lenovo as well as drivers provided by Intel for use when the native resolution is not properly detected using their normal drivers, but the issue persists.
I have also updated system BIOS as these DP ports and power management seem to have disagreements at times.
Does anybody know how I can coax the Intel drivers to send a regular 1280x1024 native resolution picture to the secondary monitor without it assuming the monitor cannot really handle it?
Other systems with same configuration work OK and send correct native resolution without issues.