How to render thousands of bullet holes with good performance?

I have done the following :

- A bullet decal which is simply a quad mesh renderer
- A bullet decal material which have GPU instancing enabled

The problem is when I put like 2000 of these game objects into a wall, there's a performance issue when I look at them.

I can see in the stats panel that rendering them increase of number of tris/verts by thousands...

The bullet holes certainly won't move and are applied to static surface so is there a way to make them not cost anything to render them ?

 

perhaps once the number of bullet holes reaches a certain number, can you replace the material/texture with a texture that has bullet holes pre-rendered onto it?