Cosine-weighted importance sampling, Resolution 1280X720, Reflection/refraction bounce limit 5, Min samples 4, Max samples 64, Min shadow samples 4, Max shadow samples 16, Sampling threshold 0.0001, Min GI samples 4, Max GI samples 16, GI bounces 10, Render time 28 minutes 5 seconds. With a cosine-weighted image, the image appears much better, especially the sphere with emission and its illumination, when compared to uniform sampling.

Uniform hemisphere sampling, Resolution 1280X720, Reflection/refraction bounce limit 5, Min samples 4, Max samples 64, Min shadow samples 4, Max shadow samples 16, Sampling threshold 0.0001, Min GI samples 4, Max GI samples 16, GI bounces 10, Render time 26 minutes 28 seconds.