Just passed the AI-900 yesterday with an 875. Took me about three weeks of studying, mostly evenings after work, 45 minutes to an hour a day. I've been in data analytics for two years but had basically no machine learning background before starting, so I wasn't sure what to expect difficulty-wise.
The exam is 40–60 questions with a 60-minute limit, which sounds comfortable but some questions are multi-select and case-study format so don't assume you can breeze through. Content breaks down roughly into AI workloads and considerations (~15%), fundamental ML principles (~20%), computer vision (~15%), NLP (~15%), and Azure AI services (~35%). That last section is the heaviest and the one I almost underestimated.
Microsoft Learn has free learning paths and they're genuinely useful for the Azure-specific content — Cognitive Services, Azure Machine Learning Studio, which service does what. I also used a paid Udemy course but the free material covered about 85% of what I needed. Don't skip the hands-on labs if you have time; recognizing service names in context on the exam is easier when you've actually navigated the portal.
Worth noting the exam can be taken online proctored now. I did it at home with no issues — just clear your desk of papers and disconnect any second monitors ahead of time or you'll waste 20 minutes on setup with the proctor.
The Azure free tier is enough to run all the AI-900 relevant labs. I used it for about two weeks and it didn't cost anything. Worth setting up just to see the interfaces even if you don't go through every single exercise.
I'm studying for this right now. How important is it to actually use the Azure portal — can you get by just memorizing service descriptions? I don't currently have a subscription set up.
Nice score. I passed with an 820 two months ago. The Azure AI services section tripped me up more than I expected — specifically questions about when to use Form Recognizer versus Document Intelligence versus Custom Vision. Know the use cases for each before you sit.
So I bombed my first OAR attempt and honestly it stung because I thought I'd done enough. My problem was I just kept reading through material and never actually drilled questions under any kind of time pressure. Second time around I flipped that completely. I spent most of my prep just doing practice sets over and over until the question types stopped surprising me, and the mechanical reasoning section was where I gained the most. This set right here was the one I ran the most, oar free oar mechanical reasoning question and answers 2, and after going through it a few times the pulley and gear stuff finally clicked instead of me guessing.
The other thing I changed was pacing. First attempt I burned way too long on the math and ran out of breathing room. So I started timing myself on everything, even short sessions after work. If you didn't pass the first go, don't assume you need to relearn it all. You probably just need reps and a clock. That was the whole difference for me.
Congrats on the 875, that's a solid score. I just want to throw in something that helped me a ton when I was grinding through OAR prep, because I burned the first week doing it wrong. I kept drilling practice questions and just memorizing which answer was correct, and my scores barely moved. The thing that finally clicked was making myself explain why each wrong answer was wrong before I moved on. Sounds tedious, and it is, but the OAR loves throwing in answers that are almost right.
Once I started doing that, the math and reasoning sections got way easier because I could spot the trap choices instead of second guessing myself. You stop falling for the answer that's technically true but doesn't actually answer what's being asked. If you've got no background in some of the content like I did, don't just chase the green checkmark. Slow down and figure out what the test writer wanted you to think, and you'll see the same tricks show up over and over on the real thing.