Meta fights soaring hardware costs by reusing old DDR4 server memory in new DDR5-only servers — custom CXL 2.0 chip marries legacy DDR4-2400 with cutting-edge DDR5-6400
…The software stack transparently exposes CXL memory as a separate NUMA node and enables Linux to migrate cold pages to the slower DDR4 tier (with 76 GB/s of bandwidth) and retain…