Dell PowerEdge R710 and NVIDIA GeForce GT 720

I have a PowerEdge R710 with Windows 2008 R2 and installed a NVIDIA GeForce GT 720. The Windows drivers appear to have installed correctly, and all looks good in the device manager, but I have 2 problems.

1. I cannot get a signal either digital or analog from the card to the monitor
2. Windows 2008 still appears to be using the built in VGA adapter

Is there a jumper on the motherboard that disables the built in adapter and enables the PCI Ex8 card, or a BIOS setting? Or is it just incompatible? Although that would be odd as Windows recognizes the card and installs the drivers without a problem.

Any help would be greatly appreciated!