Due to this VGA card has 2 DVI outputs connected to the primary GPU device, and 1 HDMI output connected to the secondary GPU device. By design, only the primary DVI connector outputs signal under DOS or during POST. The other outputs become available after the Windows display driver loads.

For more information on setting multi display in NVIDIA control panel, please follow this link from NVIDIA official website:
http://nvidia.custhelp.com/cgi-bin/nvidia.cfg/php/enduser/std_adp.php?p_faqid=2354