3 entries.
Most slow reports are not a DAX problem. They are a modelling problem, and the fix is older than Power BI itself.
A Power BI report replacing a 40-tab spreadsheet that took two days a month to assemble by hand.
power-bi · dax · modelling
The patterns that come up constantly — time intelligence, filter context, and the difference between the two X functions.
power-bi · dax