Obviously Normal Calculations are faster than table calculations. The understand the reason, please check the below steps of actions Tableau uses-
- Tableau generates a query and sends to DB.
- The database processes the query and Tableau considers all Normal Calculations and LOD here in this phase.
- Tableau generates a temporary table from the result set returned by the data base.
- Only after that Tableau performs Table calculations.
- Then generates the visualizations.
So Normal Calculations are performed at the second stage, while Table calculations are performed just before rendering the visualization. So Normal are faster.
Hope you understand. If yes, please mark my answer as helpful.