Facepunch added scene compilation to s&box. Potentially giving large a large performance boots for scenes with many models.
Instead of asking your graphics card to draw every model individually, they group many models into one large model. Cutting down the number of draw calls needed to render your scene.
In my very contrived test, I have seen 5-30% increase in fps and a reduction in draw calls by over 50%.
We dont know yet how this will affect real game performance overall. But it has the potential to be significant