Sanity Check...

If I have 2 cameras, one for my UI and the main game camera, the combination of the two renders is effectively a full-screen alpha, slowing my fill rate down loads, right?

Cheers,

SB.

Nope

As they don’t copy full quads over thats not the case, they just draw their stuff over whats there from the previous cameras render if you set them up that way
just ensure to use layers correctly etc

I dont see much of a drop when I use a second depth camera for GUI. In fact it was fog that was causing a massive slow down (6fps).

Ah, bugger - so basically it only draws what it sees? I’m using Sprite Manager for the UI, using a Second UI cam - it basically just has the impact that Sprite Manager with the standard camera does, then?