Italian hardware site ReHWolution has received some early information regarding ASRock’s unannounced TRX40 Taichi and Creator motherboards. Apparently, they’re not backwards compatible with first- or second-generation Threadripper CPUs. Ryzen Threadripper 3000 won’t work on X399 boards, either.
ASRock TRX40 Taichi & Creator coming in November. Not backward compatible with 1st and 2nd Gen Threadripper CPUs. Also, 3rd Gen TR CPUs won’t work on X399 boards.
— ReHWolution (@ReHWolution) October 9, 2019
The underlying reason between this restriction remains a mystery. We know that the EPYC “Rome” MCM is pin-compatible with first-generation EPYC “Naples” chips due to the fact that the newer chips are drop-in compatible with older servers via a BIOS update. The TR4 socket, too, is nearly identical to SP3r2, but for four out of eight memory channels being blanked out.