Market and Technology Trends

Memory-Processor Interface 2023 - Focus on CXL

By Yole Intelligence — Sep 2023

CXL might just be the key to turn today's server memory challenges into a $15 billion opportunity by 2028.

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Transitioning from prototypes to large-scale memory pools and beyond

Data center workloads are becoming increasingly complex, requiring more and more memory. Memory is a very costly resource, forecasted to reach over 40% of the server value by 2025.

Among several initiatives, Compute Express Link (CXL) has emerged as the industry choice, with its aim to enhance cache coherency, resource disaggregation, and composability in data centers. Memory will be the primary driver for development.

CXL is in its very early stages of deployment, with the first server CPUs supporting the CXL 1.1 interface, Intel’s Sapphire Rapids and AMD’s Genoa, entering mass production in early 2023. The CXL memory market is currently primarily prototypes, with an estimated market value of around $14m in 2023.

Looking forward, a first market take-off is expected by the second half of 2024, when the first CXL 2.0 CPUs enter the market, enabling the implementation of memory pools. The ramp-up will be further reinforced in late 2025 with the availability of CXL 3.0 CPUs, which are expected to expand memory pooling possibilities further and enable the composability of servers.

CXL memory expanders will employ the same form factors available for PCIe systems. In the coming years, memory media will mainly be DRAM, which could represent up to 80% of the memory expander cost.

The DRAM market for CXL is expected to be worth ~$12.5B by 2028, but it is conditional on effective roadmap execution, especially for CPUs supporting CXL. DRAM for CXL would represent 8% of the total DRAM market ($158B in 2028).

Although the market is at its dawn, future business strategies are already profiling

Servers are already facing challenges linked to memory performance, and they could benefit from CXL deployment in both the short and longer terms:

AI cloud servers, for instance, could benefit from CXL since version 1.1 for memory expansion. CXL 3.0 could enable accelerators (GPUs, DPUs, FPGAs, ASICs) to access memory pools directly.
Cloud service providers and hyperscalers are expected to show significant interest in memory pooling, starting with CXL 2.0 and composable servers with CXL3
Database servers will be able to run larger in-memory databases for faster analytics.

Add-in cards are mainly sold by expander controller providers, such as Astera Labs, Montage, and Microchip, while memory IDMs (Samsung, SK hynix, and Micron) are promoting the CXL drive form factor. Nowadays, three suppliers offer CXL expander controller chips in their portfolios: Astera Labs, Microchip, and Montage. In the case of CXL switches, most players – e.g., Enfabrica, Panmnesia, and Elastics.cloud - are considering smart SoCs with CXL switches being an embedded block of a much more complex chip. On the other hand, switch supplier Xconn intends to provide a stand-alone CXL switch chip.

CXL has the potential to revolutionize memory utilization, management, and access in terms of disaggregation and composability. This paradigm change, which already occurred in the 90s for storage, could give birth to a new industry focused on CXL memory fabric software, systems, and services.

From standard definition to mass deployment: the evolution of CXL hardware

CXL is implemented on top of the PCIe physical layer. Current CXL1.1 CPUs (PCIe 5.0) enable direct attachment of memory expanders. CXL 2.0 CPUs (PCIe 5.0)will allow CXL switches, expanding memory pooling capabilities on a larger scale. CXL 3.0 CPUs will use PCIe 6.0, allowing cascading switches and peer-to-peer connections for full server disaggregation and composability.

By combining three different protocols (CXL.io, CXL.cache, and CXL.mem), the CXL standard enables 3 CXL device types. This report focuses on memory expansion, categorized as a type 3 device.

Memory and storage technologies leveraging CXL:

Despite being media agnostic, the primary demand for CXL will be for memory expansion and memory pooling, both based on DRAM media and mainly implemented as memory expanders.
CXL memory expanders can take the form of add-in cards with DRAM DIMMS plugged in, or Drives (EDSFF form factor) with DRAM. Drives are expected to gradually take over from add-in cards, mainly because of their optimized form factor, compatibility with server chassis standards – important for cooling – and ease of handling.
Striking the right balance between cost and capacity will be key in determining when CXL drives will overtake add-in cards.

CXL memory expander controllers and switches:

The estimated cost of complex CXL expander controllers is over $60 in 2023, as they are new in the market and are on advanced nodes.
CXL switches are expected to be far more expensive due to the heavy lane configuration (x256 lanes) and aggressive technology nodes (16nm FinFET for the first prototypes).
Pricing for both CXL controllers and switches is expected to normalize with the mass deployment of CXL.

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Key Features

Overview of the semiconductor memory market.
Analysis of key trends in datacenter driving CXL demand.
Introduction to CXL with focus on memory use cases and typical server configurations.
2022-2028 forecast for CPUs, memory expanders, memory expander controllers and CXL switches (Munits, revenue, wafers…)
Technology trends for the systems abovementioned and key technical challenges to succeed their market penetration.
Supply chain and players mapping for the CXL ecosystem for memory expanders, expander controllers and CXL switches.

Product objectives

Yole is pleased to provide you with the brand-new memory report “Memory-Processor Interface 2023: focus on CXL”, offering a detailed technology and market analysis of the new Compute Express Link (CXL) interface, focusing on memory devices and the related chipset.

The main objectives of this report are as follows:

Deliver an in-depth analysis of memory technology expected to leverage the CXL interface and their markets:

Analysis of the memory bottlenecks and challenges in the datacenter space and the performance improvements CXL would bring in to address such issues.
Detailed overview of the CXL interface with a focus on the memory expansion and pooling use cases.
Overview of CPUs, memory and storage technologies with potential to leverage the CXL interface.

Present the CXL memory controllers and the CXL switches:

Technology overview of the CXL memory expander controllers and the CXL switches, necessary to enable memory expansion and pooling.

Offer 2022-2028 market forecasts for CXL memory and CXL compatible ICs:

CXL memory market with focus on DRAM for CXL shipments as well as the form factors associated to the interface (Add-In Cards and CXL drives) in unit shipments, average capacities, revenue and average selling prices (ASP)
Unit shipments, revenue, ASPs and equivalent 12” wafers production volumes for CXL memory controllers and CXL switches.

Describe the CXL ecosystem and players’ dynamics for memory technology:

Description of the players, the applications and the use cases driving CXL demand.
Mapping and analysis of the players offering CXL memory expanders, expander controllers, and CXL switches, as well as the supply chain associated to each of them.

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