Questions
Q1
Will my Hi-Fi B85N 3D motherboard support on-board display with add on PCI-E VGA card's display?

Hi-Fi B85N 3D does not support on-board display with add on PCI-E VGA card's display at same time.

However you might use three display on this board for support multi-display.

D-Sub display, HDMI display and DVI display.

After boot to Windows, driver will recognize three monitors and can use Intel graphic driver to control them right away.