Hi

I'm buying a Dell laptop, and I'm thinking of leaving Intel for AMD. I've seen benchmark tests where while running Adobe Premiere and Resolve, Ryzen 7 5800H outperforms the Intel i7 11800H (which is the other option in the Dell Gaming laptops sold here in Brazil). I've talked to people who runs echatrandom Avid on desktop models of Ryzen, but not on that specific mobile model. Has anyone?

When running Avid MC the priority should be stability over speed. Avid and Premiere are very different to each other backend, so I wouldn't look at Premiere benchmarks to compare hardware for Avid.

Although a Ryzen may perform better than intel during benchmark tests, Media Composer's code might not be written to take advantage of Ryzens architecture. I think Avid only qualifies one high-end Threadripper CPU, compared to many intel ones.  

Look into these qualified systems: https://avid.secure.force.com/pkb/articles/en_US/compatibility/en422411

These qualified systems are guaranteed to work with Media Composer. The team at Avid have ensured that these systems run composer well.

Having said that, of course, non-qualified systems will work too. I'm running a completely unqualified system: A custom-built GTX 1650 GPU and a Ryzen 7 3700x, and I have no issues, But I couldn't afford a similarly specced qualified system, and I don't have really tight deadlines looming so if anything god forbid does go wrong, I have the time and expertise to troubleshoot.

To summarise, Go ahead and buy the unqualified CPU, but know if you ever make a support case in the future, Avid will find it difficult to offer advice and support: They'll look at your hardware and tell you that's the issue, instead of looking into the software and troubleshooting that. Alternatively you could purchase a qualified system and you'll know that no matter what it will work, and it will be optimized for Avid. 

Avid using AMD CPUs has never really been an issue. They were even officially running on them back on HP xw9300's. I build a budget Media Composer system on a FX-8120 6-7 years ago that was rock solid. Back then you just needed to make sure you had a nVidia graphics card.