I have a AMD HD5770 But I have big issues with the driver. So I decided to invest in a card that is more "Ubuntu friendly".
I need a card with 2 dvi ports. Im going to run Virtualbox and some light gaming. Maybe the GT620 could meet my needs?
I went with gt630 and I'm quite happy with it. 630 is the same GPU system76 delivers with some of their computers.
With the open source driver the screens goes full retard. You need to run "sudo apt-get install nvidia-current".