Mirroring a game onto a monitor

So I want to run a tv and a monitor and have them be mirrored. So whatever is on the monitor is on the tv. So what I want to know is, Can I mirror a game the same way I would a desktop? will the computer/game care whats on the monitor? Also will It require more horsepower to run the game on two monitors at once? Or will it be the same amount of power required? Hope that was somewhat clear. Thanks

some games will be finicky (i'm looking at you counterstrike), but for the most part it should work just like mirroring anything else, i can't say for certain, but i don't think it would require any more power, as it's really only drawing the frames once and displaying them twice

You can buy a DVI or HDMI, Y-cable and that should do the trick. It will just be the exact same image on both screens although I don't know how that works if the two screens are different resolutions or anything of that nature. I would assume the larger resolution screen would just have big black bars. As far as power goes I don't think hooking up a Y-cable should cause any issues or use any more power. 

I was planing on using the dvi out to my monitor and then the hdmi out to my tv. Both monitors are 1920X1080. So all I have to do is enable mirroring and it should work good?

I would think but you never know...