The speed improvement is tremendous. Handbrake gets all 8 processors going full speed, and cuts the time to process by hours.
You have to install the amd firmware, or the screen doesn't work.
I used an msi motherboard and it all worked. I thought I was being smart and just switching the boot disk, but it goes nuts. I had to reinstall Debian.
ps. amd iommu gives trouble, and I did this link.