Find Highest 3x3 Sum

[daffodil11]

I have a dataset containing 3264 rows and 7640 columns, and I need to find the sums of each 3x3 grid, and eventually determine which are the top 10, by row & column header of upper left cell.

I've attached a scaled down version with values from B2:P29. What would an efficient approach to this be?


It's being used in conjunction with Latitude and Longitude, where each cell represents .01 degrees; actual headers are Lat and Long.
Normally I'd just use a visual heatmap but these people want data with granular detail.

To clarify, I'm mostly just looking for the list of all 3x3 grids and respective totals.