
Intel "Emerald Rapids" Doubles Down on On-die Caches, Divests on Chiplets
Finding itself embattled with AMD's EPYC "Genoa" processors, Intel is giving its 4th Gen Xeon Scalable "Sapphire Rapids" processor a rather quick succession in the form of the Xeon Scalable "Emerald Rapids," bound for Q4-2023 (about 8-10 months in). The new processor shares the same LGA4677 platform and infrastructure, and much of the same I/O, but brings about two key design changes that should help Intel shore up per-core performance, making it competitive to EPYC "Zen 4" processors with higher core-counts. SemiAnalysis compiled a nice overview of the changes, the two broadest points of it being—1. Intel is peddling back on the chiplet approach to high core-count CPUs, and 2., that it wants to give the memory sub-system and inter-core performance a massive performance boost using larger on-die caches.
The "Emerald Rapids" processor has just two large dies in its extreme core-count (XCC) avatar, compared to "Sapphire Rapids," which can have up to four of these. There are just three EMIB dies interconnecting these two, compared to "Sapphire Rapids," which needs as many as 10 of these to ensure direct paths among the four dies. The CPU core count itself doesn't see a notable increase. Each of the two dies on "Emerald Rapids" physically features 33 CPU cores, so a total of 66 are physically present, although one core per die is left unused for harvesting, the SemiAnalysis article notes. So the maximum core-count possible commercially is 32 cores per die, or 64 cores per socket. "Emerald Rapids" continues to be based on the Intel 7 process (10 nm Enhanced SuperFin), probably with a few architectural improvements for higher clock-speeds.
The "Emerald Rapids" processor has just two large dies in its extreme core-count (XCC) avatar, compared to "Sapphire Rapids," which can have up to four of these. There are just three EMIB dies interconnecting these two, compared to "Sapphire Rapids," which needs as many as 10 of these to ensure direct paths among the four dies. The CPU core count itself doesn't see a notable increase. Each of the two dies on "Emerald Rapids" physically features 33 CPU cores, so a total of 66 are physically present, although one core per die is left unused for harvesting, the SemiAnalysis article notes. So the maximum core-count possible commercially is 32 cores per die, or 64 cores per socket. "Emerald Rapids" continues to be based on the Intel 7 process (10 nm Enhanced SuperFin), probably with a few architectural improvements for higher clock-speeds.