Was going to ask the same question, I remember older chips having wafer number (apparently) & it was thought better to get a lower number. I have had very low number chips & found them no better than mid no chips so didn’t go much on it. SB now has a number printed on the board again maybe this is the wafer number & for fun I would like to know which number is from the centre of the wafer.... is it like 0 or 500 in a 1000 scale for arguments sake???