**A genuinely complete treatment of DAX performance — nothing else comes close** I've been working as a Senior Power BI Developer for years, and I came to this course after hitting the ceiling that most of us hit: you know DAX well enough to write anything, but you can't reliably explain *why* one version of a measure runs in 80 ms and a semantically identical one takes 12 seconds. This course closes that gap completely. What impressed me most is the sheer scope. It doesn't just teach optimization tricks — it builds the mental model from the ground up: the Tabular query architecture, how a DAX query is split between the formula engine and the storage engine, how VertiPaq actually stores and compresses data, and only then how to read query plans and storage engine queries to find where the time is really going. By the time you get to specific optimization patterns, you already understand the machinery well enough that the patterns feel inevitable rather than memorized. The breadth is remarkable too. It goes well beyond the classic in-memory scenarios into DirectQuery over SQL, composite models, and the performance cost of row-level security — exactly the areas where real enterprise models fall apart and where documentation is thinnest. The tooling coverage (Performance Analyzer, DAX Studio, VertiPaq Analyzer) is practical and immediately transferable; I was applying it to production models the same week. And the length is a feature, not a drawback. Alberto and Marco never rush a concept or hand-wave a detail, and that patience is precisely what a topic like this requires. Every non-obvious behaviour gets the time it deserves, usually with a demo you can reproduce yourself. The included materials — the PDF book, PBIX demos, DAX samples, SQL Server backups, and BIM files — mean you can pause and experiment instead of just watching. If you build semantic models that real people depend on, this is the single highest-return investment you can make in your DAX skills. It changed how I write measures, how I design models, and how I diagnose problems. Thank you for making material at this level available.

It was a wonderful journey, full of enriching explanation

Wow. Extreme good tematics and huge volume of information and examples. I am amazed. Thanks!

This is a very complex topic and requires solid previous knowleadge. The course itself is very well build and the book also helps a lot. Hope to use this knowleadge!

as with all SQLBI materials, free or paid, amazing!!!!!

Absolutely amazing!!!

Thank you Alberto and Marco for all these deep and profound insights into DAX and its optimisation possibilities!

Wow! Lots of great information in this video series. I am looking forward to reading the book.

As usual with SQLBI, amazing content!!

Very good course. Some technical observations. The pre-written questions made the lectures smoother. It also made the lectures smoother when you could start copying server timings from DAX studio. I'm waiting for the composite model part to come out.

Thank you Alberto and Marco for all the information given. It is very impressive to gain this knowledge. Thank you. Guido

Very nice course filled with knowledge you will hardly find elsewere. You see, a relatively new PowerBI Developer can make beautiful dashboards, but only a small percentage masters Dax and it's optimizations. This course is very dense/very technical in terms of content but I would say it is absolutely essential for developers with lots of users. At a corporate level you will have users with bad internet connections (even more with the advent of remote), and you will probably (as myself) have to present Dashboards on Teams Meetings - which quite often - slow the performance of the share. This to say that even if you write perfect code/ and have a perfect model (which dont exist) there are other factors that will degrade your dashboards performance, so it is absolutely essential you know optimizations - otherwise you will have users complaining and eventually the quality of your work will be questioned lol. Even though I am not finding the course "enjoyable" it's a must. Like eating vegetables, I would rather have a pizza but legumes are essential..

This is an excellent course. I have already used the learnings to optimise several of my reports! I love that the course encourages an empirical approach, where you test different designs with different data distributions. The course avoids the dogmatic one-size-fits-all advice you sometimes get in code reviews, where it is assumed there is only one right way to do things.

I am a hobby user of DAX and power BI and very interested in this matter. I followed this and other courses at sqlBI, because I was curious how it worked behind the screen with Vertipaq, I started taking this course. A world has opened up and I found it clearly explained. The thing I found annoying is that sometimes columns in the model had to be made visible and I could only do this by installing SQL server and then creating my own Power BI document via power query (smaller (10M) because my laptop didn't have enough memory). Maybe in the future make all columns immediately visible in Power BI and then also in the smaller files. Although I have studied DAX as a hobby, this will also apply to my work. Not in the financial world, but in delivered products (assignments) vs Year Target. Keep following you on YouTube. Greetings Coro Lamoré in the Netherlands

Enjoyed a lot this course! A lot of useful and practical information. Great work guys!