Arm debuts Neoverse CSS N4, its next-gen semi-custom chip design platform, and says it supports 8 to 128 Neoverse N4 cores at up to 3.8 GHz on TSMC's N3P node (Jake Roach/Tom's Hardware)

Arm has unveiled its next-generation Neoverse CSS N4 'Ranger' platform, featuring up to 128 cores per die on TSMC's N3P process. The Compute Subsystem (CSS) is a semi-custom program that tailors the chip design to specific customer needs, including core count, cache size, I/O, and connectivity. Neoverse CSS N4 supports eight to 128 Neoverse N4 cores, running up to 3.8 GHz, though exact clock speeds per configuration remain undisclosed.

The platform scales beyond 128 cores with support for multi-chiplet and multi-socket designs, as well as UCIe chip-to-chip interconnects and partner-specific PNYs. It supports DDR5 or LPDDR6 memory, along with up to 256 MB of L3 cache per die and 2 MB of L2 cache per core. I/O capabilities include up to 128 PCIe lanes and CXL 4.0.

Arm claims Neoverse CSS N4 delivers twice the socket performance, 1.25x performance per watt, and 1.75x memory bandwidth compared to the Neoverse N3 platform. The N-series cores are optimized for performance per watt, while the V-series targets maximum performance. Notable customers include AWS, Nvidia, and Google Cloud, which have previously utilized Neoverse V-series cores for their cloud-based workloads.

The announcement focuses on those building on the CSS platform, leveraging Arm's validated building blocks for semi-custom silicon creation. Arm's AGI chip, built with Neoverse V3 cores, will also deploy the new CSS N4 platform, though performance benchmarks remain undisclosed.