I'm working on a project in Blender 2.78. Normally I work from my fancy workstation. Last night, I pulled up my project on my laptop in Blender 2.76b (that's the newest version that works on my laptop). I did some more modeling and saved the file. Today, I opened the file up in 2.78 again and the render quality has dropped dramatically. I'm using an environment map for lighting. Even when I pump the samples up, the quality is horrible. When I create an area light with an emission shader, the quality is as expected, but the environment light has suffered.
Here's a screenshot that compares the render quality using an environment texture for lighting. Notice the quality difference and the number of samples in each image:
Why has my render quality dropped?
Can I fix my file or should I create a new .blend and append the objects from my original file? (that seems to fix the problem, but it's not an ideal solution since I will probably be doing more work on my laptop).