Yes, keep all the intermediate stuff in arrays then write to the sheet at
the end.

here is a simple example reading and writing about 260000 cells

option base 1
option explicit
sub SteCheck()
dim vArr as variant
dim j as long
dim k as long

'read from a sheet into a variant
vArr=Worksheets("MySheet").Range("A3:Z10000")
' varr now contains a 2-dimensional array of worksheet data

for j=lbound(varr,1) to ubound(varr,1)
' loop on rows
for k=lbound(varr,2) to Ubound(varr,2)
' loop on cols
varr(j,k)=varr(j,k)+j*k
next k
next j

' write result back
Worksheets("MySheet").Range("A3:Z10000")=varr

end sub

Charles
___________________________________
The Excel Calculation Site
http://www.decisionmodels.com

"Ste Mac" wrote in message
...
Hi Charles, wow, this is interesting can you give me an example
please...

So, you are saying do not write anything to the sheet until the end?

Ste