Rocket Lake (RKL) is Intel’s new micro-architecture that will be a direct successor to the Comet Lake-S series of desktop CPUs and high-performance mobile devices. These were expected to hit the market by the end of this year, but the roadmap from Intel paints a different picture.
Intel has been using the same iteration of the 14nm FinFET process node with the Skylake Architecture for many years. Comet Lake-S was also fabbed on this aging process node, which has held Intel back in terms of IPC uplift and efficiency gains over AMD’s Ryzen lineup. Rocket Lake-S desktop platform is going to be the last CPU architecture to be based on an advanced 14nm process node. Intel’s Rocket Lake will use a 14++ nm back-port of the Willow Cove core architecture. Rocket Lake is going to be the desktop equivalent of Tiger Lake.
Now, as per one recent finding which was spotted by @momomo_us, coming via Videocardz, one MSI Infinite B915 pre-built system’s Russian PDF manual confirms that MSI is offering Rocket Lake-S support on the entry-level H410 motherboard chipset. This board will support Rocket Lake-S chips having a TDP of up to 65 Watts.
This doesn’t come as a surprise though, since it was already rumored before that the upcoming 11’th gen Rocket Lake-S CPU lineup will support the 400-series Motherboard chipset. Previously, it was confirmed via WccfTech, that the Rocket Lake-S desktop CPUs are only going to be compatible with the Z490 chipset and LGA 1200 socket motherboards, since Motherboard vendors heavily advertised that these boards are PCIe-4.0 ready. But now it appears that the mainstream and low-end 400 series boards are also going to offer support for Rocket Lake-S.
GIGABYTE has already confirmed that their Z490 AORUS lineup of motherboards support limited PCI-E 4.0 capabilities on Comet Lake-S CPU lineup, which makes sense given these processors do not support all the features of the PCI-e 4.0 interface. But since hardware-level support for PCIe 4.0 is already built-in these Z490 boards, only Rocket Lake CPUs are going to offer full compatibility with the PCIe Gen 4.0 standard. PCIe- 4.0 has been an AMD-only feature within the consumer market till now, but things might change with the launch of Rocket lake-S CPUs.
When it comes to the Rocket Lake-S CPU lineup, I have another important last piece of info to share with you. Previously few months ago, one VLSI engineer who goes by the name Retired Engineer on Twitter, @chiakokhua, tweeted one of his old findings from November 2019 last year. According to him the upcoming Rocket Lake-S processors are going to feature ‘multi-chip modules/MCM’ of core and uncore GPU dies built on different silicon fabrication nodes.
This is speculation from his side, but he has a strong record of accurate prediction in the past, when he spoke about the 3rd gen Ryzen Matisse AM4 processors being multi-chip modules as well. Apparently, it might be possible that Intel is also designing these socket LGA1200-based Rocket Lake processors to feature multi-chip modules, similar to Matisse in some ways. According to the block diagram posted by @chiakokhua, it appears that Rocket Lake-S is a multi-chip module consisting of a 14nm die that holds the ‘CPU cores’; and a 10 nm die that holds the ‘uncore’ components. But in the case of Rocket Lake the uncore die is more advanced that the CPU die.
The CPU die is fabbed on a 14 nm node on Rocket Lake-S, which contains the Willow Cove CPU cores in this die, and a system agent, which are connected together by a Ring-bus interconnect. And the system agent connects to the 10nm uncore GPU die via EMIB. The 10 nm GPU uncore die on the other hand features the Gen12 XE iGPU with up to 96 EUs, a dual-channel DDR4 memory controller, a PCI-Express 4.0 controller, as well as display and media engines. Rocket Lake-S MCM provides a total of 24 PCI-Express lanes, out of which 16 are assigned as PEG (PCI-Express Graphics), and 8 lanes are assigned as chipset bus. Previous gen Comet Lake-S CPU lineup only provided us with 20 lanes.
This is not the first time Intel is taking the MCM approach. Clarkdale, first-gen desktop processor supporting the LGA1156 package was an MCM having a 32 nm CPU die, and a 45 nm uncore graphics and integrated memory controller die. It remains to be seen whether Intel really chooses the MCM approach with the Rocket Lake- S lineup of desktop processors.