Second dedicated graphics card; mixing Nvidia and AMD

Hey all!
I have been doing more rendering in Blender which is a fantastic piece of FOSS, but one of the issues I’m hitting is that my GeForce GTX TITAN X alone is not doing the job quick enough. I’ve always wanted a graphics card from AMD, and I have heard that people who render 3d objects often have two graphics cards. My question is whether I could get a new AMD card, hook it up to be my secondary card, and still be able to utilize both the Nvida and the AMD cards for my Linux system?