Are there performance toggles that I am missing?

I've been out of the Unity loop for a bit, and I had an old project that involved building meshes out of cube faces generated at runtime. Similar to a Minecraft setup. I got some really good performance out of it:

I went and checked out some later work on the project, and its framerate had been cut down dramatically, to about 60-65!fps. I wanted to find what was causing the performance drop, but I couldn't find anything.

So I figured, hey, let me try rebuilding it. I created a new project, threw a single cube in the scene (GameObject->Create Other->Cube) and loaded an empty scene. I ran it. The performance was terrible:

I've been racking my brain but I can't seem to figure this out. How can something with 16 draw calls, and 162.3k verts, and actual code running during updates, by so dramatically faster than a scene with just a single cube, 1 draw call, 24 verts, no scripts running, nothing?

This is on the same machine, running one project after another. Can anybody give me an idea of something to look at? It feels like I must have changed a setting or something to get the great performance out of the original, that is not a default setting? I can't figure out what else it could possibly be.