Running three monitors on GNU/Linux using two graphics cards?

Question

Is it possible, and practical, to use two graphics cards in GNU/Linux to run three monitors?

Currently I have one R280X which supports two monitors, and in some cases three. In my case, I probably cannot use this single card to drive three monitors, as the three monitors are all different, and use DVI.

Can I then simply obtain a cheap, secondary graphics card, insert this into a free slot, and connect my third monitor to the new, secondary card?

The R280X would drive two monitors over DVI.

The new card would drive one monitors over DVI.

What problems could I face with this? Is it notoriously difficult to set up? Are there any limitations I should be aware of?

Such as, can I seamlessly drag windows between all three monitors? What about accelerated video? Will I only see accelerated video on the two monitors connected to the R280X?

Answer 1

Yes, it's possible and practical.

If you use Xinerama (which is the default), you can seamlessly drag windows. Accelerated video is a difficult topic, and will depend on details of your setup. In general, accelerated video should work as long as the complete window is either on one or on the other card. Don't expect it to work if your window sits across both cards, at least not with acceleration.