Third monitor via motherboard

[IAmHomeboy]

I am running a Dual monitor setup on my sapphire radeon 7850 2gb. I have recently gotten a new monitor, and i was wondering if i could attach it to my motherboard ( asus m5a78l-m ) I tried to do it but it did not show any signal. What have i done wrong?

 

[ThatVietGuy]

Typically the onboard video gets disabled when there is a PCIe graphics card attached.

 

[nukemaster]

You may need to ensure onboard video is enabled. You also have to tell Windows to use the extra screen(it is in with the display resolution section).

Last off, some boards disable the onboard video when a dedicated card is presented(your board seems to support both at once).