Hardware Configuration, Audio/Video
Many Radeon cards are compatible with FreeBSD.
Nvidia cards haven't always been compatible with FreeBSD, but recently they are and have video card support.
Use the program xrandr to be able to use and configure multiple monitors. With this program, a basic video card can use both of it's HDMI and DVI outputs for dual configured monitors.
Example of command line that can be used in the file .xinitrc:
xrandr --output DVI-0 --right-of HDMI-0
To see the obsolete way of configuring dual monitors for Nvidia cards, see Dual Screen