GameObjects load problem

Hello everybody!

I'm trying to make a game minecraft like, and i'm having problems with GameObjects load on Unity3D.

I have a Cube, with a material texture with 180 bytes. And when I try to start the game with more then 30k cubes, I take about 3 minutos to start and is sooo laggy...

There is any better way to load a huge ammount of objects then simple creating a new GameObject?

This is my code:

 GameObject newCube = GameObject.CreatePrimitive(PrimitiveType.Cube);
 GameObject model = GameObject.FindGameObjectWithTag("MyModel");
 
 newCube.transform.position = new Vector3(x,y,z); 
 newCube.renderer.material.CopyPropertiesFromMaterial(model.renderer.material);
 newCube.renderer.material.name = model.renderer.material.name;