Architectural details of Intel's next-generation Diamond Rapids "Xeon" processors are starting to emerge. Information from the kernel patch indicates a significant shift from the previous architecture, where computing and memory controllers were highly integrated. Now, these have been divided into two distinct chip modules, each with specific functions: the CBB (Core Building Block) focusing on computing, and the IMH (Integrated I/O and Memory Hub) managing I/O and memory controls.

This architectural division signifies a clear strategic direction. Unlike Granite Rapids, which retains the IMC within the compute module, Diamond Rapids separates the memory controller from the CBB and places it into an independent IMH chip. This decoupling frees the CBB from the responsibility of handling memory and peripheral interface logic, allowing its design to concentrate on factors such as core count, frequency, and power efficiency, while the IMH handles platform-level I/O, memory topology, and scalability.

Based on the patch details, Diamond Rapids is likely to be integrated with up to two IMH chips, operating in parallel with multiple CBB compute modules, all situated on a unified base package. This resembles the Clearwater Forest concept but executed at a substantially larger scale and complexity. For Intel, this represents a move towards a more systemically cohesive structure, enabling the simultaneous expansion of core counts and I/O bandwidth by augmenting module numbers rather than intensifying functional density within a single chip.

This structural modification also influences the discovery mechanism and performance monitoring design. Diamond Rapids maintains reliance on discovery tables for non-core unit enumeration, albeit through a bifurcated implementation: IMH-related PMONs are enumerated via PCI, whereas CBB PMONs are accessible through MSR. Each module possesses its own discovery tables, no longer relying on a singular global entry point. This segmentation adds software complexity but offers enhanced module decoupling, especially beneficial in multi-chip, multi-slot setups, supporting superior scalability and isolation.

Furthermore, Diamond Rapids integrates new PMON types encompassing inter-chip interconnects, unified buffers, caches, and I/O systems, extending to PCIe Gen6. In comparison to Sapphire Rapids, the IIO free-run counters transition to an MMIO-based model, boosting the observability of peripheral and interconnect behaviors. These advancements aim to prioritize platform-level monitoring and optimization as core sizes and power demands escalate.

A key I/O feature of Diamond Rapids is its PCIe Gen6 support. This interface standard is anticipated to become dominant in future data center platforms, and Diamond Rapids, along with forthcoming Venice models, are designed with this interconnect in mind. The enhanced bandwidth per channel will accommodate denser accelerators, expanded networks, and augmented storage capabilities, yet it necessitates meticulous attention to packaging, signal integrity, and power management—underscoring the IMH's standalone importance.

Currently, detailed information about the compute scale is scarce. However, it is confirmed that Diamond Rapids will employ the 18A process and Panther Cove P-Core. Rumors suggest core counts could reach up to 192, with some speculating as high as 256 cores. The platform is expected to make use of the LGA 9324 socket, featuring a maximum TDP of 650W and supporting multiplexed configurations. Such specifications indicate Diamond Rapids is tailored for extreme data center demands, emphasizing platform-wide scalability over single-chip control.

The pivotal transformation in Diamond Rapids lies not in its specific parameters but in its redefinition of modular boundaries. By distinctly separating computing, memory, and I/O functionalities, Intel is forging an architectural path to accommodate immense core capacities, extraordinary power requirements, and next-gen interconnect standards. The ultimate test will be whether this architecture justifies its complexity costs, a question that will be answered as the correlated platform and software ecosystems evolve.