And it works quite well. This is with 2 LCD monitors on my 4850 and a 32" LCD TV on the onboard 3200,
Also if yours is anything like mine and the option is there, make sure to set the clock frequency for the onboard to at least 400-500 MHz,
as well as giving it a minimum of 256 MB of ram, assuming you have at least 2 GB of system ram.
Surround view turns on the onboard VGA as a secondary graphics output for a 3rd monitor as the 4350 can have 2 monitors.
Up to 4 actually. Two on the video card, and any combination of DVI/VGA or VGA/HDMI on two of the three (unless the motherboard manufacturer only used two ports, most have three) on the motherboard.