The A Twitter user (YuuKi AnS,@YuKi_AnS) released two PPTs last week about Intel Granite Rapids and Sierra Forest series of Xeon CPUs, which we can take a look at together.
Currently, Intel has the Eagle Stream microarchitecture platform, including the existing Sapphire Rapids-SP and the upcoming Emerald Rapids-SP CPUs, which are all based on the LGA 4677 slot.
For the next generation of Xeon chips, Intel will use the new Mountain Stream and Birch Stream platforms, which are designed for high-end Xeon chips such as Granite Rapids-AP and Siera Forest AP. Let’s start with a look at the features of the reference Avenue City platform.
The Avenue City reference motherboard can be up to 16.7×20 inches in size, has 20 PCB layers, includes two LGA 7529 slots, supports Granite Rapids and Sierra Forest-AP CPUs, and supports a 500W TDP.
The platform has 24 DDR5 DIMMs supporting 12 lanes of memory, six PCIe Gen 5 x16 links (Gen5 / CXL) and 6×24 UPI links.
The Granite Rapids-AP CPU is said to offer up to 128 cores and 256 threads and will be HBM style as shown in the ES / engineering samples.
When it comes to memory, these 24 DDR5 DIMM slots can accommodate 6400 Mbps speeds for 1DPC and support 8000 Mbps in the MCR.
The Avenue City reference platform also includes two PCIe x2 M.2 slots, a PCIe x2 M.2 (2280) module and a PCIe x1 LOM (Springville), and offers a number of I/O interfaces such as rear USB 3.0 + USB 2.0, serial port (Type-C), Mini DP, Gigabit Ethernet port, RunBCM module (AST2600), as well as TPM 2.0, SPI TOM module and PFR 4.0, among others.
Regarding this motherboard, Intel also lists the applicable chassis, one is the 2S open chassis standard EGS POK and the other is the 2S 4U enclosed chassis (Rich AIC).
As far as we know, Avenue City is part of the Birch Stream platform and not part of the Mountain Stream platform. In fact, there’s not much known about the Mountain Stream platform yet, but for now it’s safe to assume that Granite Rapids will be an all-big-core product, expected to use Intel 4 process and the latest Redwood Cove cores, while Sierra Forest is an all-E core design, primarily for compute/efficiency density core load, designed to compete with the AMD Bergamo family (Zen 4C).
According to Intel planning, Granite Rapids Xeon CPU is expected to be launched at the end of next year, Sierra Forest is also expected to be launched at the same time, but given Intel’s frequent delays, we dare not say for sure.
