CXL (Compute Express Link)

CXL (Compute Express Link) is a next-generation high-speed interconnect technology designed for heterogeneous computing architectures in AI data centers and high-performance computing. Built on top of the PCIe physical layer, it allows different types of compute units (CPU, GPU, accelerators, etc.) to efficiently share memory with low latency. This enables memory pooling and dynamic resource allocation, providing greater flexibility for future computing needs.

CXL consists of three main protocols, which can operate independently or together depending on the scenario:
．CXL.io: Similar to PCIe, it handles data transfer and device management while providing lower-latency I/O operations.
．CXL.cache: Allows peripheral devices to directly cache and access CPU memory while maintaining data consistency.
．CXL.memory: Enables the CPU to access device-attached memory while keeping data consistent.

Further reading: Revolutionizing the AI Factory: The Rise of CXL Memory Pooling

With the rapid growth of generative AI, system performance bottlenecks have shifted from raw compute to data transfer efficiency. Even as CPU performance improves, memory channel bandwidth limits prevent hardware from reaching its full potential, creating the so-called“memory wall.”

This limitation is common in traditional servers, reducing efficiency and often leading to overprovisioned memory and wasted resources. With CXL, the CPU can treat memory from different sources as a single logical space, overcoming the capacity limits of motherboard slots. This modular design also simplifies system upgrades and maintenance and allows AI data centers to build shared memory architectures for low-latency, high-throughput dynamic resource allocation, supporting variable and data-intensive workloads.

GIGABYTE servers have been validated and optimized for CXL technology. By providing high-speed, cache-coherent interconnects between CPUs and devices, they improve resource utilization, support large memory expansions, and reduce latency compared to direct DRAM connections. This makes them especially suitable for generative AI, HPC, and cloud applications that require heavy data processing.

GIGABYTE server CXL memory expansion solutions, such as those on the R284-S91 and R263-Z39 models, include:
．CPU & DIMM DRAM: Fastest access via traditional memory.
．PCIe-Attached DRAM: GIGABYTE servers are validated for CXL, supporting memory expansion via E3.S PCIe or additional cards for greater flexibility.
．Storage-Attached Memory: Memory expansion through storage devices, enhancing scalability and resource allocation via SSDs/HDDs.