SK Hynix's Optical Interconnect Memory Roadmap: Connecting Larger Shared Memory Pools via Localized HBM
Odaily News, Citrini analyst jukan stated on the X platform that at first glance, SK Hynix's CPO technology roadmap appears to have one axis pointing toward HBM and another toward optical communication. However, the underlying logic is that AI competition is shifting from individual chip performance to data transfer efficiency across the entire system.Over the past few years, HBM has addressed the problem of GPUs being unable to receive data fast enough. By vertically stacking multiple layers of DRAM and placing them next to the GPU, HBM delivers extremely high bandwidth. Yet, as more HBM stacks are placed around each GPU, packaging area, interposer edge space, power supply, and thermal dissipation capabilities are all approaching their limits. Meanwhile, AI clusters have expanded to thousands or even tens of thousands of GPUs. No matter how fast a single GPU computes, the entire system will still be constrained by the "bandwidth wall" if data cannot be efficiently transferred between GPUs and racks.SK Hynix's vision is to extend optical interconnect to memory. Low-latency, high-bandwidth local HBM will remain next to the GPU, while optical fibers connect it to a larger shared memory pool. This approach avoids limiting all memory capacity within a single GPU package and enables horizontal scaling at the rack level.From an investment perspective, this does not mean HBM will be replaced in the near term. What is more likely to emerge is a new memory hierarchy: frequently accessed data remains stored in local HBM, while larger-scale, less frequently accessed data is stored in optically interconnected memory pools, HBF, or SSDs.SK Hynix is repositioning its business, shifting from selling standardized memory chips to co-designing HBM, controllers, advanced packaging, and system-level memory architectures with customers. If this roadmap comes to fruition, SK Hynix could strengthen customer stickiness, increase product added value, and enhance its ability to secure long-term contracts. At the same time, the company may also more proactively address the potential impact of future memory disaggregation on traditional HBM business models.At the supply chain level, areas that may benefit in the long term include silicon photonics chips, optical engines, lasers, fiber coupling technology, and advanced 2.5D and 3D packaging.However, this concept is still in its very early stages and essentially remains just a roadmap. jukan noted that a person involved in TSMC's packaging business whom he interviewed today was completely unaware of this plan.
