DRAM

Understanding STREAM: Benchmarking Memory Bandwidth for DRAM and CXL

In today’s Artificial Intelligence (AI), Machine Learning (ML), and high-performance computing (HPC) landscape, memory bandwidth is a critical factor in determining overall system performance. As workloads grow increasingly data-intensive, traditional DRAM-only setups are often insufficient, prompting the rise of new memory expansion technologies like Compute Express Link (CXL). To evaluate memory bandwidth across DRAM and CXL devices, we use a modified industry-standard tool called STREAM.

In this blog, we’ll explore what STREAM is, how it works, why it’s commonly used for benchmarking memory bandwidth, and how a modified version of STREAM can be used to measure performance in heterogeneous memory environments, including DRAM and CXL.

How To Extend Volatile System Memory (RAM) using Persistent Memory on Linux

Intel(R) Optane(TM) Persistent Memory delivers a unique combination of affordable large capacity and support for data persistence. Electrically compatible with DDR4, large capacity modules up to 512GB each can be installed in compatible servers alongside DDR on the memory bus.

Intel’s persistent memory product can be provisioned in a volatile “Memory Mode” which replaces DRAM volatile capacity with the persistent memory capacity, and persistent “AppDirect” mode which presents both DRAM and persistent memory to the operating system and applications. Both modes are explained in more detail here . It is possible to configure a system to utilize a percentage of persistent memory as volatile and persistent, but this mixed-mode still provisions all the DRAM capacity as a Last-Level Cache.