slow cycles render for a fully enclosed box

I’m trying to render the interior of a concrete tunnel which is fully enclosed except for 4 door openings with a number of ceiling fluorescent lights as the emitters. The render times in cycles are tremendous to remove all the graininess.

I’ve reduced the bounces to max 4 and min 1, but it still takes over 11 minutes to do a 1000 passes render with very basic materials and I haven’t even put the other face-heavy objects in there yet. Is this just what I have to deal with if using cycles, that it will be quite slow for the benefit of photo-real renders?

I can’t use GPU, as it’s not supported on my machine, but have i7 at 3.4GHz

How much are you lighting this, and can we see somthing yet to get any ideas? If you aren’t doing so much GI in there, then maybe drop to 1 and 1 on bounces, or 2 and 1. Are you using any AO in the scene or anything to help light other than the ceiling lights?And for 1000 samples, 11 minutes isn’t bad.

IS the scene fully textured? I’ve often noticed that interior scenes with lighting that produces noise generally clear up better when there is more variation in the colours (ie textured walls) in the scene.

Edit: Try turn diffuse reflection bounces to 0, so for diffuse surfaces you will have direct lighting. THat should clear it up a fair bit faster.

Edit edit: Alternatly try another render engine, this below render was done on LuxRender CPU Only with the BiDirectional Path Tracer and Sobol Sampler: 2 minutes and 14.33 passes.