Ray Tracing isn’t on, it’s on Classic 3D. I just purged the cache and set Ray Tracing to the GPU (unsupported) and it still basically freezes when I add the camera layer. I just barely managed to undo the action of adding the camera layer and once the camera layer is gone the comp runs fine.
To make a quick test I just created a new composition with a blank white solid, two lights, and a camera layer. I even animated the solid to move away on the z axis and rotated the camera around it while the two lights were shining. Everything worked fine.

What’s going on? :\