Problems with object collision detection using mesh colliders

So I'm working on a project and I need to detect when an empty object with a mesh attached to it collides with another object. Essentially, I want to know when the mesh is touching a cube. I've tried using the mesh collider (And it works) but the problem is: I have a circular mesh and therefore need to Inflate the mesh. This decreases its accuracy and increases lag by a lot and I can't have that happen.

TL;DR: I copy my mesh to a mesh collider but the mesh collider is inaccurate and laggy.