How do Laptop GPU's Work?

[Captain Kalabraxo]

Hello,

 

I know this may still like a stupid ass questions to ask but as I was look at my Nvidia Control Panel to Set my 840M to my main GPU I saw that after I applied the settings my Laptop + 2 External Monitors where being fed off of my Integrated GPU on the die and I got confused... So, how do Laptop GPU's work?

[Alim]

Frames are copied from nvidia gpu to intel cpu and then sent to monitor(s)