Actually I'm not aware that all 3 Monitors will turn on together (probably not)
But the 2 DVIs can, if your graphics card allows expanding to two monitors (probably yes)
So it's 3 no (together that is) and 2 yes
By the way, depending on your m/b and video card you can have more than 2
But I'll leave that to the hardware experts, to hopefully provide some links
In the meantime, please go to your video cards manufactures support website, and try to find info on dual display setup