Not sure if it is the fastest but my approach would be to put ColA New and
ColA Old into an array, scan the array for differences and write a new colI
value where the same. I experience faster response than reading each row in
directly from the sheet.

--
Cheers
Nigel



"Glen" wrote in message
...
I was wondering which method people would recommend to do teh following.

There are two workbooks Old.xls and New.xls. I need to compare the
value/string in each cell in Column A in Old.xls with the cells in Column
A
in New.xls. When matched then the value in Column I in Old.xls must be
added
to the value in the corresponding row in Column I in New.xls

So...is it better to do row by row comparison and a single addition
between
workbooks?

Or should I create an array from the Old.xls with just Column A and Column
I
and then do the comparison and addition?

Or should I create ranges of Column A in the New.xls and do the comparison
with an Intersect function?

Or...?

There are always better ways to do things and I would like to see what
others have experienced.

thanks