Connecting to one big table vs multiple smaller tables

[DaxPadawan]

Hello! Our users have 8 stores and we want to consolidate all the data into a dashboard. The original plan was to have on big table with a dimension to determine which property it belongs to, but it was also propose that each store has their own "data warehouse".  

Would there be any significant difference between having one big table and having 8 tables from different warehouses? I'm guessing the latter may cause some performance issues. 

[Brunner_BI · Accepted solution]

If you import everything in Power BI it does not matter anymore where the data came from (besides the refresh time).

It can be much faster if you have a good star schema and not everything in one big fat table.

Columns are more a problem for Power BI than a lot of rows