No I was opening the attribute table and right clicking on the field then choosing calculate geometry.
I did it in ArcMap 10.5.1 and it took 26.04 seconds on 265,953 records
I did it in ArcGIS Pro 2.9 and it took 55.83 seconds on 26,953 records
I'll try the Calculate Geometry Attributes tool to see if there is a difference.
Amanda Bishop, GISP