With the cost of new RAM soaring, Meta has found a thrifty way to reuse older memory in newer servers.
The performance of about 40% of Meta’s millions of servers is limited by a lack of memory, the company said — but it has a surplus of older DIMMs from decommissioned servers, because RAM chips can last about twice as long as the rest of the machine.
To address this imbalance, Meta developed a custom Computer Express Link (CXL) chip it calls Vistara, along with associated software, to decouple older memory from server memory channels and enable its reuse in new machines alongside their native memory. Using the older RAM through the CXL interface does not significantly affect performance — an outcome that would not have been possible by plugging the older DIMMs directly into newer servers.
