Supported GPU

Hi!

I recently acquired a Dell PowerEdge R720 and have questions about GPU compatibility.  The Service Tag for the system is 

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2 x Xeon E5 2620's

76GB RAM

Nvidia Tesla K20m GPU

I need to put a GPU better suited for video encoding/decoding than the model Tesla I have and would really like to use a Quadro P4000.

I've read conflicting reports on this and figured this would be the best place to get confirmation.  The card is going to cost me a few hundred dollars so I want to make 100% sure.

Is there a published list of the supported GPU's for the Dell PowerEdge R720?  

If you say no, the P4000 wont work, can you explain why/if there are any workarounds.  And could you also suggest a comparable (and compatible) card for me to try please?

Thanks in advance!