New Power BI guide says import data first and use live modes only when they fit
Reviewed by Helen Jones
James Serra published a full rewrite of his Power BI performance guide on 23 July 2026. It replaces a 2022 feature list with a practical decision framework for how reports should load data after Microsoft Fabric and Direct Lake matured. The guide treats performance as a chain: source preparation, storage mode, semantic model design, DAX, report layout, security, refresh, and Fabric capacity. Import remains the default starting point for interactive reports. Direct Lake is aimed at large Fabric Delta tables with framing refreshes. DirectQuery is reserved for near-real-time needs, source-enforced security, or data too large to import. Composite and hybrid models mix modes only for specific freshness and scale tradeoffs. It stresses measuring the real bottleneck before changing architecture, and keeping Delta tables healthy if you use Direct Lake.
For years, many reporting teams treated storage mode as a background setting. Import was the quiet default, DirectQuery appeared when someone wanted live numbers, and slow dashboards got blamed on DAX or visuals. Fabric then added Direct Lake language in meetings without a clear rule for when it helps a normal business report. This update makes the tradeoff explicit. Storage mode now decides freshness, memory use, query path, and capacity pressure. Live and lake-backed modes push cleanup and modelling upstream. If the source is messy or the Delta tables are poorly maintained, the report does not just run slower. Totals become harder to reconcile with Excel, refresh ownership gets fuzzier, and stakeholders lose trust faster.
Analysis
Treat this as a decision checklist, not a reason to rebuild everything on Direct Lake. Pick one slow or disputed Power BI report, write down its current storage mode and why it was chosen, then compare that choice to the guide's Import-first criteria. Only change mode if you can name a concrete freshness, size, or security need that Import cannot meet.
Source note
Pulse published by Collab365 Spaces, reviewed by Helen Jones on . Cite as "New Power BI guide says import data first and use live modes only when they fit", Collab365 Spaces. 3 sources referenced.