By Dick James
An interesting confluence of events has occurred in the last few months, starting with the announcement at the Intel Accelerated event in July that Amazon would be one of Intel Foundry Services (IFS) first customers, specifically for packaging.
On November 30 – December 3 Amazon had their AWS re:Invent gathering, at which they launched their Graviton3 data centre processor. Unlike the earlier Graviton and Graviton2 devices, Graviton3 takes the chiplet route with seven dies and a total of 55 Bn transistors.
The dies at the sides of the core processor chip are DDR5 memory controllers, and those at the bottom are PCI-Express 5.0 controller chiplets. Reportedly a 5nm TSMC process is used, and it runs at 2.6 GHz, dissipating 100W, a little less than the 110W of the Graviton2. It appears that 50 Bn of the transistors are in the processor die.
The processor has 64 cores stitched together with a mesh that runs at >2 GHz and has more than 2 TB/s bandwidth. 32 MB of cache memory is spread through the mesh, which with the core caches adds up to 100 MB of cache on the die. The DDR controllers are DDR4800, giving over 300 GB/s memory bandwidth.
Given the look of the Graviton3 package, and the Amazon/Intel IFS packaging statement, it leads me to wonder if the chiplets are linked with Intel’s EMIB (Embedded Multi-Die Interconnect Bridge) technology. Two plus two could give 22, but in Intel’s last quarterly call we have the comment that since March they had shipped their first IFS packaging units for revenue. Graviton3 parts are now available to preview the new Amazon EC2 C7g instances, so they are clearly out there in AWS servers.
The final confirming link for me is that the interconnect bump pitch is reported to be 55 µm; which is what EMIB uses.
So, two plus two could still give 22, but it seems to me that it’s at least likely that Graviton3 uses EMIB to hook those chiplets together, and AWS is IFS’ first revenue customer.