Do you have the latest 4-1 drivers from VIA installed. The BIOS has little effect but the AGP miniport drivers do. They are on version 4.16 last I heard. Also there are some BIOS settings that might need to be changed (disable pallet snoop is one I think).
Make sure Windows haas no conflicts with the device in start/control panel/system/device manager/display addaptors.
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