Just cut and pasted this from a NORIA newsletter email today. Sure it's old news to most the folk here but i found it interesting: Book Bits: Do Synthetics Reduce Friction? From "How to Select a Motor Oil and Filter for Your Car or Truck" Some synthetics, such as diesters and polyol esters have natural lubricity. Other synthetics, such as PAOs, offer no enhanced antiwear or friction-reducing properties by themselves. However, formulated motor oil generally consists of a blend of base oils plus additives that collectively impart friction and wear-reducing performance properties. PAO is the most common synthetic fluid used in motor oil formulations. It is frequently blended with a small concentration of an ester, such as a diester, to reduce seal shrinkage, improve additive solubility and provide better lubricity. However, it is worth noting that a mineral oil can be blended with esters and antiwear additives to achieve similar results.