This is more a question for the After Effects folk, and probably better posted on their forum. I can move it there if you like.
Yes, I think "puppet" in this case is the AE puppet tool.
Moved the Ae forum
AE doesn't really rely on video cards very much. You'd get one more for its use in OTHER applications.
Now, what DOES matter in AE CS6 is fast processors and lots of RAM.
can a flat layer that I would bend or curve be rendered only through ray tracing?
In CS6, yes.
Well, there are some third-party plugins that do that too.
Now, if you do plan to use the ray-traced renderer in CS6, please get a GPU in the 700 series from NVIDIA. Anything newer won't work to accelerate the ray-traced renderer.
If you get a newer version of AE, all of what I just said changes.