The R620 wasn't intended to be used with video cards, so you may run into some issues. The first problem would be getting the extra power carried to the card with the 8 pin connectors, but the other issue is that the card may lead to stability issues. You can get messages such as "Bus Fatal Error at X:X:X," which would keep the server from POSTing. That having been said, some people in the forum have done similar things and reported it working once loaded into the OS. I wouldn't recommend it, if what you have in mind is buying a card specifically for this server, as opposed to testing something you already have.