In a side-by-side comparability utilizing 1.6 Tb/s ports, optical cables can eat as much as 20 watts of energy, vs. just about none for copper.
That hole has main implications at scale. In huge AI installations with hundreds of connections, optical energy draw can rapidly add as much as a significant share of a facility’s whole vitality utilization.
Regardless of its effectivity, copper has a tough bodily limitation: distance. As knowledge charges enhance, the utmost size of passive copper cables shrinks dramatically.
At frequent speeds—akin to 1Gb/s—copper Ethernet cables can span lengthy distances with out subject. However on the speeds used inside AI methods, the story modifications. At roughly 200 Gb/s per lane, passive copper connections are restricted to only some meters, usually round two to a few meters. Past that, sign integrity breaks down and fiber turns into inevitable, stated Shainer.
This constraint shapes how trendy knowledge facilities are constructed. Copper is right for scale‑up networking, akin to connecting GPUs inside the similar rack, the place distances are brief. Scale‑out networking—linking racks throughout rows, halls, or whole buildings—requires fiber optics.
Fiber additionally matches copper in uncooked pace potential. Each media can help extraordinarily excessive knowledge charges, however fiber maintains these speeds over vastly longer distances. The tradeoff is increased value, higher fragility, and considerably increased energy consumption. Copper cables are bodily robust and tough to wreck. Fiber cables include delicate glass strands that may break if bent or mishandled.
