Microsoft has a pretty good relationship with AMD from the Xbox. AMD already made an Arm Opteron. Windows has been multiplatform since NT 3.1 (Alpha, MIPS) and

Microsoft has a pretty good relationship with AMD from the Xbox. AMD already made an Arm Opteron. Windows has been multiplatform since NT 3.1 (Alpha, MIPS) and then in 3.51 adding in PowerPC. You can download Windows for Arm for free and run in on a Raspberry Pi. Microsoft has at least one homegrown processor that it has ported Windows and Linux to with the confusingly named 'Edge'. https://www.theregister.com/2018/06/18/microsoft_e2_edge_windows_10/ https://www.theregister.com/2018/06/18/microsoft_e2_edge_win... Microsoft doesn't even _need_ to target Arm, they could easily team up with AMD or go the whole thing solo and target anything from RISC-V, Arm to an in-house ISA.