Expect backward compatibility to make a return for 4th and 5th Gen Threadripper. In a post explaining why it went with a brand-new socket (more data pins were required for increasing bandwidth), AMD mentioned that sTRX4 would be supported on a “near- and long-term basis.” The implication is that Threadripper 4000 and 5000 should slot nicely into most TRX40 motherboards.