if you have a lot of formulas which are not currently needed, copying and
paste special values over the top of them will open up the dependency tree.
the thing that causes full recalc is the number of dependencies in the
formula memories. for calcs which only have to be done occasionally but are
the same for a column or row. leaving the first as a formula and pasting
special on the rest will allow you to just copy and paste the formula over
the range when you do need re calcs
on some files I have set specific macros just to do cals on spcific columns.
(you don't wnat to know how long it takes to do 52 columns by 60000+ rows of
sumproduct calculations on 12 arrays 60000+ long)