Amazon’s Graviton3 processor has 7 chips, 64 cores and three-socket motherboards

In a word: After being announced six months ago, Amazon has finally discontinued its third-generation Graviton processors in its AWS instances for rent. Amazon also revealed its one unique feature: exactly three of them fit into one motherboard, no more, no less.

Amazon’s Graviton series is the line of Arm processors that it designs and produces itself, for itself. It makes them available virtually through AWS (Amazon Web Services) to the public and businesses of all sizes; Amazon proudly announced that Epic Games, Formula 1 and Twitter were testing and loving Graviton3 instances ahead of last week’s release.

Amazon didn’t go into detail with the specs, only saying that the Graviton3 has 64 cores in its compute chiplet. With all its chiplets combined, it has 55 billion transistors, almost twice as many as the Graviton2 and more than even the 64-core AMD Epyc Rome processor.

You can spot the seven chiplets in the diagram below. In the middle is the monolithic compute matrix with all the cores. To the south of this is a pair of PCIe 5.0 controllers and flanking the sides are four DDR5 controllers which, based on the schematic, each handle two lanes.

Amazon claims the Graviton3 is 25% faster per core than its 2020 predecessor. In all-core scenarios, its floating point and crypto throughput is doubled and its machine learning performance is tripled. Not bad, even if the Graviton2 only had a quarter of the hearts: 16.

AWS C7g instances using the Graviton3 are now available with up to 64 vCPUs, or a full processor. In its maximum configuration, the system has 128 GB of DDR5 and 30 Gbps of network bandwidth. Instances are available up to 1 vCPU (core) as usual.

ServeTheHome notes that Amazon treats each processor as a separate node, which is perhaps why they can fit three on a motherboard. And the how: Instead of using a parallelized approach that would lend itself to two or four sockets, each motherboard is connected to a Nitro board that handles all of the networking, security, and storage.

It’s a shame that Amazon doesn’t sell the Graviton3 and its chipset because it would be great to play around with. AWS can’t help but go from strength to strength.

Leave a Comment