Did you install drivers for each card??
In a 2 card setup I had sometime ago,I needed to run the driver install for each card,can't remember how I went about it though
![Roll Eyes](https://bitcointalk.org/Smileys/default/rolleyes.gif)
Maybe through device manager..............
Yes you should go to device manager, then find Display Adapters and click update on any thing there that have a yellow !
This should update you to the latest drivers of your display adapters (graphic cards)