When I look in my preferences/shaders/# of lights, the walls of my industrial building are glowing bright red. I retexed the walls with new brickwork, etc., but I did not increase the resolution or do anything unusual. The .dds is saved as BC3/DXT5. I have all the lights cranked down real low but the FPS is way down to 10-20 in some places. Due to the layout on the inside of the building, I can't do much else to optimize the cell. Here's a top down view:
http://i744.photobucket.com/albums/xx90/MDC519/Hotwalls.jpg
Anyone else had this problem and can give me some advice?
Thanks

Did you remember to save the textures with mip maps? Also, depending on the actual implementation of lights, they may be applied to the entire scene. You could try to delete a few to see the effect.

Yes they have mip maps. I'll try and disable a bunch of lights and see if that has any effect. Thanks.
I went in and deleted the lights in 1/2 of the building and my walls went green. Most of the lights had less than 200 radius. I was using EnclaveLightFillNeutral with the same interior emittance. I do not have a ton of lights. How would the lights be applied to the entire scene?

Having the light radii intersect and the number of light objects in a cell creates more lag than just about anything else. When you toggle the "L" button, do you see your light radii intersecting? If so reduce the number of lights and their radii to minimize the intersection. This will help quite a bit. If you find your cell too dark, just increase the overall lighting of the cell versus adding more light objects. As to why this occurs, I can only guess that it takes quite a lot of GPU processing to calculate the inter-relationship of intersecting lights on all the objects n the cell.

I didn't think to take a look at the radii that way and I did have a lot of intersections especially near the outside walls. Part of the problem was that I have a tall building with pod modules stacked on top of each other. Since I couldn't optimize the normal way (you could still see the top level of pods from the basemant area) the lights were real close on top of each other. I finally managed to get a nice compromise by continuing to lower the light levels (radii) and increasing the cell ambient light level like you suggested. Now the FPS is almost double what it was before and much smoother. Thanks much!