Arm has published the first Chiplet System Architecture (CSA) specification and is claiming 60 companies are engaged with the CSA initiative. Arm aims the CSA at customers developing infrastructure chips incorporating its Neoverse CPUs. Whereas customers have had the option of licensing RTL (soft IP) and hard IP (which Arm calls CSS), they can now obtain from Arm a CPU die (chiplet) to package with other silicon to complete a chip.
Notables
- Merchant-market chiplets have been slow to take off. High-bandwidth memory (HBM) has been the most successful example.
- Computing chiplets are a reasonable next step. Standardized in operation and often licensed technology, a CPU cluster will have well-defined I/O, enabling designers to treat it as a discrete monolith. Multiple cores with cache can be sizeable; hiving them off into a standalone die should improve manufacturing yields.
- IP licensing is a high-volume, low-price business. By forward-integrating into chiplets, Arm can raise prices without encroaching on customers’ businesses.
- Spec development is boring but required for merchant chiplets to gain acceptance. The CSA spec covers topics such as interfaces, SoC components such as management controllers, and security.
- Arm is underappreciated for its ability to advance projects like CSA that promulgate its CPU architecture while also helping chipmakers reduce time to market and increase downstream customers’ acceptance.
Bottom Line
The CSA initiative is good for Arm. It should help the company capture additional value and raise adoption of the Arm architecture in infrastructure designs. It’s also beneficial to chipmakers that require high-performance CPUs but focus on other chip functions. Arm already points to demonstrators such as a data-center AI processor integrating a Neoverse chiplet and Rebellions AI accelerator. We expect Arm to have customers making general-purpose server processors based on Neoverse chiplets and proprietary I/O dice (ala AMD Epyc) and others developing communications-infrastructure products combining Neoverse and networking dice. At the chiplet industry’s early stages, it takes companies like Arm to create specs and release the first products.