Two graphics cards - what when where how?

[GameDevKev]

I have read that you can run two graphics cards at once, but I could not find much specifics about running dual graphics cards. First of all, I couldn't find any info on if they have to be the same? In my case, I have one for gaming, and one on the cheap as a backup. Can I install both of these, or do the gpu's have to match? If they are allowed to be different, how does your computer handle them? Please link references so I can read up more on the subject. TIA

 

[Anencephalus]

Dual-installing graphics cards for Nvidia is called "SLI" and for AMD it's called "crossfire".

You don't always need the same card but to prevent any additional possible issues it is recommended to get the same card. For different cards you will need to look up if they are compatible with each other.

Also please note that even with the same card, it does not mean you won't run into any problems. Other than installation, driver, or other issues there are also possibilities of the SLI/crossfired cards being incompatible with some games. Usually though you can just run the game off one card.

Here is an excellent post by Maziar that will hopefully help you.
http://www.tomshardware.com/forum/245454-33-crossfire-faqs

Good luck