For 3 monitors to be used at once, you will need at least one ACTIVE DisplayPort adapter. You can find more information at http://www.amd.com/us/products/technologies/amd-eyefinity-technology/how-to/Pages/faqs.aspx , but one of your 2 DisplayPort adapters will need to be swapped out to an active adapter to get all 3 up and running (check www.amd.com/dongles for a list of certified adapters).
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