Zuck saves Meta bucks by reusing memory from old servers with a custom CXL ASIC

Meta is recovering DDR4 memory from old servers, installing it in new machines, and using a custom Compute Express Link (CXL) ASIC to share the memory across applications – without encountering latency problems. The social networking giant calls its tech "Vistara" and will present it at ISCA 2026 on Monday, but The Register found the company's paper ahead of the talk. The document opens with the admission that Meta can't increase the amount of memory in around 40 percent of its vast server fleet