This tutorial shows how to adjust 3 parameters when moving a file from version 8.0 to 8.1. These are the anti-aliasing threshold (Block Volume Subdivision Limit), Adaptive Surface Sampling, and Adaptive Shadow Sampling. The way version 8.1 uses these values has shifted and this tutorial shows how to adjust them when opening an 8.0 file in 8.1.
Download the layered PSD file shown in the video and examine it along with the tutorial. The video compression and scale will make some of the artifacts and quality issues discussed difficult to see without the psd file.
For a video specifically going over anti-aliasing thresholding in version 8.1, go here.
For a video specifically going over adaptive shadow sampling in version 8.1, go here.
