Arm launches Neoverse CSS N2: a near-complete chip design that customers can quickly convert into a finished product.

On Hot Chips, Arm Neoverse launches CSS N2. CSS stands for computing subsystem. This is a more or less finished blueprint for a data center CPU based on the Neoverse cores. Arm’s design is a bit surprising as it is very complete. Traditionally, the company primarily develops designs for components such as computing cores. Customers such as Marvell, AWS and Ampere can then work with these core designs and build their own processors on top of them.

The wheel

This approach allows them to make enough different chips, but it’s also time-consuming. Arm now argues that most of the work involved in designing chips with specific cores shouldn’t be done twice. Configuration, layout (placement of components), thermal considerations, cooling… are all already taken into account and all the key components to make the whole thing work are in place. Neoverse CSS N2 is a very complete design almost ready for the chip shop.

Licensees can still tinker with the design. Arm designed it so that adding custom chiplets with accelerators isn’t too difficult. Then customers just have to tweak I/O and memory a bit and that’s it. Customers appreciate the scalable efficiency of the Neoverse platform, but don’t want to reinvent the wheel. In theory, the new licensing model could accelerate the market for more ARM-based chips for servers.

specifications

Neoverse CSS N2 is configurable with 24, 32 or up to 64 Neoverse N2 cores. The clock frequency ranges from 2.1 GHz to 3.6 GHz. Arm is aiming for an advanced 5nm manufacturing process, leaving the details up to the customer to decide. The design supports eight (LP)DDR5 channels and four times sixteen PCIe/CXL channels. Arm also offers the ability to glue designs together in one or two sockets for 128 to 256 cores in a server.