Can Direct Lake Semantic Model compete with SSAS Tabular Live Connection in Speed?

Hi  - thanks for posting to the community.  The short answer is, it depends  - maybe, maybe not.  

With the assumption that the direct lake model is well optimized, compressed, with v-order, etc.  (see links below)...

If both are called from a cold cache then SSMS will most likely be faster because direct lake needs to warm up.

Once the cache is warm they will likely be comparable; direct lake will perform very well, like import mode. 

There are a lot of other factor that play into this though.  The links below are good reads on points to think about and also demonstrate how to capture performance metrics for the semantic model.  Then you would also want to review the Fabric Capacity Metrics App to see how the tests impacted the capacity.

SSAS vs AAS vs Fabric Semantic Models: Ultimate Showdown!

Understand Direct Lake query performance - Microsoft Fabric | Microsoft Learn

Learn how to analyze query processing for Direct Lake semantic models - Microsoft Fabric | Microsoft Learn

(25) Choosing SSAS Over Power BI for Data Modelling (On-Prem) : Case Study | LinkedIn

Migrate from Azure Analysis Services to Power BI Premium: Migration scenarios - Power BI | Microsoft Learn

Microsoft Fabric: Not All Delta Tables Are Created Equally

Migrate Azure Analysis Services to Power BI - Microsoft Fabric | Microsoft Learn

Anusha66