If you add a lot of queries to one workbook, Excel will slow down trying to constantly update the values. A good solution for this is to turn formula calculation into "Manual" in Excel's settings; with this setting, the values will only be updated when you press F9 (or you can add a button for refreshing, see "How can I add a button that updates all the functions I've placed?" below).
One thing that can really slow down the workbook is using "volatile" functions in your formulas and function parameters, as these cause Excel to constantly recalculate the formulas. The volatile functions that should be avoided are:
- INFO (depending on its arguments)
- CELL (depending on its arguments)
If you need to use the current date in your parameters, it's better to use the custom getToday() function that we include in the workbook (in v. 2.3 and newer), rather than Excel's default TODAY().
Note that Supermetrics Data Grabber runs multiple queries concurrently and can thus fetch data much faster.