I had a first time experience last night.  A model of a sheet of paper had a texture map with texts and images.  A small square edge section of it was sort of translucent, something not in the texture map.  It took me a while, but I finally got it to render correctly by changing the "Filtering" drop down menu in the texture editor from "Fast Mip Map" (the default) to "Sampling".  Other choices are "Summed Area Table" and "Gaussian Filtering".   I've never changed these before, it was just random fix trys.  What are these parameters, and when should they be used?  The manual (V.7, sheesh) says the quality changes, but does not even mention "Fast Mip Map".