AMD’s next generation of server processors come in two versions: Genoa starts in 2022 as Epyc 7004 with up to 96 Zen 4 cores including synchronous multithreading (SMT), that’s 192 threads. Bergamo will follow in the first half of 2023 as a private branch with 128 so-called Zen-4c cores on a conveyor.
In the case of Genoa, AMD confirms that the chip manufacturer TSMC is ordering the necessary chipsets with an improved 5nm process. The I/O module connects DDR5 memory and communicates via PCI Express 5.0 to GPUs, expansion cards, and SSDs. Based on PCIe 5.0, Epyc-7004 CPUs also support the Compute Express Link (CXL) communication protocol. In an email notification, AMD wrote, “Genoa is expected to be the world’s most powerful general-purpose computing processor.”
At CXL, AMD is focusing on PCIe RAM. GPU or AI accelerators over CXL aren’t an issue with the message, but AMD already has a self-designed Infinity Fabric to deliver its Instinct cards. The company recently announced the Instinct MI200 computing monster.
A leak was already published in August 2021, according to which AMD sticks to CPU cores with eight compute cores each and uses up to twelve of them in the Epyc 7004. In addition, Zen 4 is said to be able to speed up computing commands for the first time. Using AMD AVX-512.
Zen 4c without SMT?
AMD hasn’t revealed much about Bergamo, except for 128 Zen 4c cores, which are “Zen 4 compatible software” and are supposed to offer “maximum thread density” for cloud data centers. According to previous rumors, AMD is refining the pipeline with Zen 4c and above SMT in order to fit more cores in a small chip.
With this approach, each CPU core will consume less electrical power and will be better protected against side channel attacks because many threads will not have to share CPU core resources i.e. arithmetic units, registers and cache. AMD will notably eliminate the sails of ARM server processors, which typically use many efficient CPU cores without SMT.
subordinate YouTube channel speculated ‘Moore’s Law’ even before the announcementThat within a few years, AMD was able to combine Ryzen processors with Zen 5 and a proprietary, lightened Zen 4 core as a hybrid design. For the first time, Intel is using this type of hybrid computing with Alder Lake, alias Core i-12000.