Intel Announces Sierra Forest Xeon CPU With 288 Cores

Intel's Innovation event is underway today, with the company showing off its latest wares and plans for the future and mentioning "AI" every few minutes. During the Xeon portion of the CEO's keynote, Pat Gelsinger pulled a "one more thing" maneuver by revealing a version of its upcoming Sierra Forest Xeon CPU with 288 E-cores, double the number it had previously made official. As it turns out, those sneaky Intel engineers were able to just drop a second 144-core chiplet on the package, which is reminiscent of when Apple announced the M1 Ultra SoC after not mentioning it had a high-speed interface on its edge that allowed two M1 Max chips to be connected.

Gelsinger revealed the dual-chiplet Sierra Forest chip in today's keynote (YouTube link) and said it was meant to be a surprise. It certainly was, as the 144 E-core version it previously announced seemed capable of going head-to-head with AMD's 128-core Bergamo chip, though AMD's Zen 4c cores offer two threads per core, whereas Intel's do not. That puts Intel's 144-core chip at a disadvantage for cloud providers that need maximum cores and threads, at least compared with Bergamo.

The big boy chip ironically uses only little E-core dies. Credit: Intel

However, with 288 E-cores available, it will top the 256 threads in AMD's Zen 4c offering. Intel previously stated Sierra Forest and its E-core design would offer a 240% boost to performance-per-watt compared with its existing Sapphire Rapids P-core CPUs, but it's unclear what that number is for the 288-core version. Gelsinger just said it would provide huge opportunities for cloud provider scaling. He also said he still remembers when Intel announced a four-core CPU and that it indicates he is getting old. We feel you, Pat.

Sierra Forest is due to arrive in 2024, and as Tom's Hardware notes, it will be manufactured on the company's Intel 3 process. This node is a refined version of Intel 4 it's using for Meteor Lake while also being a node jump from 7nm to 5nm. No client products are expected to be made with Intel 3 as it's for server chips only. Each die has two I/O dies attached made with Intel 7 (10nm). Intel's Granite Rapids server chip features a similar design but with three chiplets, posing the question of whether Intel could make a three-chiplet Sierra Forest SKU with 432 cores—which might be problematic from a size and thermals standpoint.