Others have mentioned tighter tolerance in the cable and PCB parameters. Each successive frequency increase has required more complex PHY design. On the digit

Others have mentioned tighter tolerance in the cable and PCB parameters. Each successive frequency increase has required more complex PHY design. On the digital side : more sophisticated bit encoding schemes On the analog side : tighter tolerances for clocking and signal jitter, more sophisticated transmitter and receiver technology (better emphasis/deemphasis, better equalization) Here's taste of the PHY changes : https://www.chipestimate.com/Type-C-USB31-PHY-Challenges-in-Analog-and-Digital-Design/SilabTech/Technical-Article/2016/02/23 https://www.chipestimate.com/Type-C-USB31-PHY-Challenges-in-...