Gentlemens (and Ladies)!
I want to congratulate us all with one small won. After continuous communication with ASUS support (especially with Margarita!) now your may see ALL current Ryzen processors supported officially for ROG Crosshair VI Extreme. List now included even not so common 2300X, 2500X, 2600E, 2700E. I also must say that this apply not only for consumer products, but also for "Pro" business products! In total there are 61 Ryzen processor! New Ryzen 3000XT models also wasn't forgotten and now support since BIOS 7704.