Intel demonstrates Sapphire Rapids processor using HBM in BGA package
In a document at the end of last year, Intel confirmed that the fourth-generation Xeon scalable processor, Sapphire Rapids, will support HBM memory, but Intel did not disclose the specific configuration. According to a report by TomsHardware, at the recent International Symposium on Microelectronics hosted by IMAPS, Intel demonstrated for the first time the Sapphire Rapids processor using HBM and confirmed that it will adopt a multi-chip design.
According to Intel’s introduction, this HBM-based Sapphire Rapids processor can choose not to use DDR5 memory and use HBM memory as the main memory (just like Fujitsu A64FX processor) or can choose to mix DDR5 memory and HBM memory. At this time, HBM memory is more like a large cache, between the processor and DDR5 memory.
Image: Tom Wassick/@wassickt
As can be seen from this demonstration of the Sapphire Rapids processor using HBM, Sapphire Rapids has four small chips, each corresponding to two HBM memory stacks, and the memory bit width is 2048 bits. At present, in JEDEC’s HBM2E specification, the highest data transmission rate is 3.2 GT/s, but SK Hynix has started mass production of a version with a data transmission rate of 3.6 GT/s last year. This means that the Sapphire Rapids processor with HBM can have a maximum memory bandwidth of 3.68 TB/s, but the memory capacity is limited to 128GB. In addition, the BGA package used by the HBM Sapphire Rapids processor, because the LGA 4677 space is already very limited, there is no way to provide enough space to accommodate the HBM stack.
The use of HBM memory can bring a high-performance memory subsystem, but it also means that there will be a higher frequency, and TDP, power consumption, and heat generation are issues that need to be faced. According to Intel, this Sapphire Rapids processor with HBM will only be provided to specific customers, mainly in the field of supercomputers. In addition, the small chip using HBM’s Sapphire Rapids processor may be different from the ordinary Sapphire Rapids processor.
