We need a county breakdown to know where to go for evidence.
Using my 46,285 number (comparing total votes for President compared to the non-runoff Senate seat). In other words, this is total votes for President in excess of the Perdue Senate rate. Trump vote percentage next to the raw number.
Chatham 1,581 (40%)
Cherokee 1,304 (69%)
Clayton 1,299 (14%)
Cobb 2,974 (42%)
DeKalb 3,150 (16%)
Forsyth 1,038 (66%)
Fulton 3,886 (26%)
Gwinnett 2,659 (40%)
Henry 1,033 (39%)
Richmond 1,048 (31%)
Those are the counties with differences over 1,000. Those ten counties are a little under half. The rest is spread among the rest of the state.