The 448G copper bottleneck has moved: Luxshare-Tech's chip-side CPC is resonance-free to 110 GHz, close to PAM4's 112 GHz, but links with first-gen external twinax-to-twinax connectors stay clean only to 100 GHz. First-gen passive copper will likely start on PAM6, under 1 m.

At 224G, passive copper shrinks to 1 m and the 1-6 m zone belongs to AECs. Molex and Broadcom's answer is not thicker wire but skew specs, co-simulation and retimer telemetry; 1.6T AECs ramp in 2027 and overtake 800G only in 2030.

At the same 500 m, pluggables draw 23 pJ/bit while OCI needs 7, a gap of about 230 W per XPU. Broadcom says Ethernet scale-up is in production, copper gets one more in-rack generation with 400G PAM6, and optics must match copper power to enter.