According to the specifications of the graphics controller, HDMI and VGA could support up to 2560 x 1600.
If you are setting up extended desktop mode, you would be able to obtain 1080 on one monitor and the other 1600*900.
This is called screen panning, see here for more information: Graphics Drivers — Multiple Displays Frequently Asked Questions (FAQ)
I did think of that, but the monitor is in a different room to the TV. That would make it difficult.
Any other ideas?
Thanks for trying to help. Please let me clarify.
1 X HTPC below TV connected to AVR via HDMI.
1 X VGA monitor in office (other room) connected to HTPC via 75ft VGA cable.
I have read some third party document that for resolutions of 1600×1200 and above a 25ft or 7.5 m maximum cable can be used.