Ideapad L340 Lenovo, Good for 3D in Aftereffects?!

That entirely depends on what 3D plug-ins you are referring to and what kind of work you plan on doing. Unless those specifics are clear, nobody can answer your question halfway properly. It's the old gag of every 3D program out there using OpenGL, but each of them different implementations and sub-sets of features favoring specific GPUs and features. No different for these plug-ins.

Mylenium