Found this recent Tom's Hardware about Windows Server 2025 supported CPUs. This is what it mentions about AMD CPU list: https://www.tomshardware.com/pc-components/cpus/windows-server-2025-supports-cpus-packing-two-to-192...
On the AMD side, Windows Server 2025 supports all of AMD's modern EPYC-based CPUs, from Zen 2 to Zen 5. It features the AMD EPYC 7002 series, 7003 series, 4004 series, 8004 series, 9004 series, and 9005 series. Unlike Intel's support list, Microsoft did not test any mainstream consumer Ryzen processors.
However, Microsoft notes that the list of supported processors above does not determine actual support. The list is a mere pre-requisite for system certification, meaning only systems with the above CPUs can be certified to run Windows Server 2025. These CPUs won't be the only ones certified either; Microsoft will update the list with future CPUs as time passes.
Another tech site that mentions the same thing about AMD processors for Windows Server 2025: https://hudsonvalleyhost.com/blog/microsoft-reveals-complete-list-of-supported-cpus-for-windows-serv...
Today, Microsoft made a significant announcement regarding the general availability of Windows Server 2025, which was released alongside System Center 2025. Along with this, the tech giant has updated its list of supported CPUs to accommodate the processors compatible with this latest Server release.
The updated list includes Xeon Scalable Processors (SP) ranging from 2nd Generation to 5th Generation, as well as Xeon 6 SP, and various Xeon E and D SKUs. Additionally, several modern Pentium chips have also been added. On the AMD front, the support extends to EPYC 7002, 7003, 8004, 9004, 9005 series, and more CPUs.
The organization emphasizes that the roster of supported CPUs mentioned earlier serves merely as a requirement for system certification and does not dictate actual support. This list will be periodically refreshed to incorporate the latest processor releases:
IMPORTANT: The compilation of supported processors presented above does not, by itself, confirm Microsoft’s backing for Windows Server. The listing acts as a necessary condition for system certification. Only systems built upon these approved processors are eligible for Windows Server certification. Microsoft will routinely assess the processor list corresponding to a specific OS release and will amend the list as new suitable processors become available in the marketplace.
Since May of this year, Microsoft has been engaged in testing compatible hardware and software for certification and in September, it delivered a significant update on its progress.
So most likely all Ryzen Threadrippers will be supported on both Windows 2022 & 2025 but not officially to be certified by Microsoft for those Windows Server OSes.
If you need Windows 2022 or 2025 to be certified by Microsoft then you will need to have installed one of the processors listed for those OSes.
Good chance in the near future more Ryzen processors including the Threadrippers might be included once MS finishes testing those processors.
Otherwise the company you need to contact is not AMD but Microsoft Support since they are the one that determines which processor can be used to certify their Windows Server Oses.
