Server-class DDR3 SDRAM memory buffer chip

IBM System i®, System p®, and System z® servers require an efficient ultrareliable high-performance memory subsystem. The fourth-generation IBM advanced memory buffer (AMB) chip provides industry-leading performance, scalability, and reliability for the double-data-rate 3 (DDR3) synchronous dynamic random access memory (SDRAM) subsystems employed across a wide range of server platforms. The new IBM AMB employs a cyclic redundancy code-protected packet-protocol-based 6.4-Gb/s host channel, as well as dual 9-byte/10-byte wide 800 to 1,333-Mb/s SDRAM interfaces with dynamic calibration for optimal signal integrity under varied device and system environmental conditions. Applications support industry-standard dual inline memory module (DIMM) and low-latency high-capacity proprietary DIMM packages in conventional multichannel and redundant array of independent memory system architectures. A fully configured daisy-chain topology contains up to 256 GB of memory per host channel. This paper describes the IBM AMB chip architecture, design, and key engineering aspects.