I have four TL-PA9020's and they perform fairly well. HOWEVER, two are on one electrical circuit and two are on a different electrical circuit (in the same panel). I realized that one circuit is "odd" and the other circuit is "even". (Residential electric panels are built so that one phase feeds all the odd numbered breakers and the other phase feeds the even numbered breakers. That way, a 240v single phase circuit can be created by plugging a double wide breaker that spans phase 1 and phase 2. (Like for air conditioners, electric ovens, electric dryers, etc.)
Would I be likely to improve performance by moving breakers around to ensure that all of the Powerline adapters are on the same phase? Still on two circuits, but both circuits on the same phase?