Is it possible for me to utilize the processing capabilities of multiple graphics cards, even if I'm only using one monitor? I recently bought a new AMD graphics card, fairly top of the line. I also have a two year old, decent nVidia card. They're obviously very different cards. I don't really mind for gaming because my current card can handle most games fine by itself. I'm concerned about video editing programs such as Adobe Premiere and After Effects.

Would the system be able to utilize the power of both cards to, say, render a video? I have both drivers still installed on my machine. And because there is only one monitor connected to my current graphics card (AMD) the nVidia would be connected to no display. So I am wondering whether it would or could be utilized in some way to help in processing video. Thanks!