Add-in Cards Help Meet Expanding Server Memory Needs

CXL-compatible cards provide space- and cost-effective way to add server memory.

Spencer Chin, Senior Editor

April 24, 2024

2 Min Read
SMART Modular CXL Add In Cards ease memory expansion.
CXL Add In Cards from SMART Modular enable users to easily expand server memory for memory-intensive applications.SMART Modular

At a Glance

  • Add-in cards allow memory expansion with lower-capacity DIMMs than using higher capacity DIMMs.

As high-density data center applications become more commonplace, design engineers have to grapple with adding memory capacity in a cost and space-effective manner. SMART Modular Technologies, a division of SGH  has introduced a family of Add-In Cards (AICs) which implements the Compute Express Link (CXL®) standard and also supports industry standard DDR5 DIMMs. According to the company, these are the first in their class, high-density DIMM AICs to adopt the CXL protocol.

The SMART 4-DIMM and 8-DIMM products enable server and data center architects to add up to 4TB of memory in a familiar, easy-to-deploy form factor.  Built with advanced CXL controllers, the add-in cards eliminate memory bandwidth bottlenecks and capacity constraints for compute-intensive workloads encountered in artificial intelligence (AI), high-performance computing (HPC), and machine learning (ML). Attempts to add more memory via the traditional DIMM-based parallel bus interface are becoming problematic due to pin limitations on CPUs, so the industry is turning to CXL-based solutions which are more pin-efficient.

CXL also enables lower-cost scaling of memory capacity. Tom Quinn, Senior Vice President of Business Development, said in an interview with Design News that the add-in card is a more cost-effective means of adding memory than just using DIMM modules. According to Quinn, using an 8-DIMM CXL AIC with 64-GB DDR5 DIMMs would cost 33% less per terabyte than using eight 64 GB DDR5 DIMMs.  Replacing high density RDIMMs with a greater number of lower density modules can lower system memory costs.  

Related:Micron Exec Says Vehicles Are Next Hotbed for Memory

The add-in cards are available in type 3 PCIe Gen5 full height, half-length (FHHL) PCIe form factor. The 4-DIMM AIC (CXA-4F1W) accommodates four DDR5 RDIMMs with a maximum of 2TB of memory capacity when using 512GB RDIMMs, and the 8-DIMM AIC (CXA-8F2W) accommodates eight DDR5 RDIMMs with a maximum of 4TB of memory capacity.  

The 4-DIMM AIC uses a single CXL controller that implements one x16 CXL port, while the 8-DIMM AIC uses two CXL controllers to implement two x8 ports, both resulting in a total bandwidth of 64GB/s. Both AICs offer enhanced security features with in-band or side-band (SMBus) monitoring capability. In order to accelerate memory processing, these add-in cards are compatible with SMART’s Zefr ZDIMMs.

About the Author(s)

Spencer Chin

Senior Editor, Design News

Spencer Chin is a Senior Editor for Design News, covering the electronics beat, which includes semiconductors, components, power, embedded systems, artificial intelligence, augmented and virtual reality, and other related subjects. He is always open to ideas for coverage. Spencer has spent many years covering electronics for brands including Electronic Products, Electronic Buyers News, EE Times, Power Electronics, and electronics360. You can reach him at [email protected] or follow him at @spencerchin.

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