I have a GTX 670 and an Asrock MB. I game on my main monitor plugged into the 670. My second monitor is plugged into the MB, powered by my i5-3570K's HD graphics 4000 engine - I don't use the second monitor when gaming, except maybe to monitor the processor or video card. My thought is that I don't want the second monitor taking resources from my GTX 670. When working on documents and general computing/internet, it is very useful to have the second monitor. I can drag windows from one monitor to the other and even span across both when I want to. When not gaming and using both monitors, they both display everything with great quality.