Apple's patent offers a glimpse into the possible future of its chips

Apple has patented a hybrid memory subsystem that comprises at least two types of memory: a low-density, high-bandwidth type of DRAM and a high-density, low-bandwidth type of DRAM. Most likely, these are technologies that the Cupertino giant will use in its future SoCs, but we cannot exclude that they can be used in other chips. We recall that patents do not always materialize in products available on the market, but it seems that Apple has incurred large expenses to patent this new technique in a wide range of jurisdictions around the world, which implies that the company is really aiming at it a lot.

Apple's move to its M1 SoCs from Intel CPUs and AMD's dedicated GPUs is significant as it significantly changes the system architecture of its Macs. Dedicated CPUs and GPUs have their own subsystems memory, while SoCs usually rely on a unified memory architecture. UMA (Unified Memory Architecture) has several advantages over dedicated memory subsystems, but also a major disadvantage: in a UMA system, the CPU and GPU must share memory capacity and bandwidth, which can affect performance. in certain scenarios.

The HBM2 and HBM2E memory types provide very high bandwidth, but they cost and consume a lot, and cannot be upgraded by the end user. Conversely, creating a high-capacity memory subsystem with enough bandwidth for a high-end GPU using conventional or GDDR-type memory is not always feasible. In an effort to combine the best of both worlds, Apple has patented a hybrid memory subsystem that combines HBM-type and DDR-type DRAM types. The patent, which goes by the name of "memory system that combines high-density, low-bandwidth memories with other low-density, high-bandwidth memories", describes various SoCs that use high-bandwidth DRAM caches and core DRAMs high capacity. The patent strictly covers System-On-Chip, so all DRAMs should be soldered to the substrate or motherboard, just like the LPDDR4X chips Apple uses on its M1. The architecture described in this same patent indicates that Apple does not provide for the use of standard memory modules, at least with some of its hybrid memory subsystems.

The patent mainly covers various physical implementations of different memory subsystems. hybrid consisting of DRAM caches and primary DRAM interconnected using numerous technologies. However, it is not specified how operating systems or software might benefit from such a technology. Apple's hybrid memory subsystems certainly look very interesting, but it is unlikely that this type of hybrid technology will be exclusive to the company. In fact, modern Intel Xeon Scalable processors can work with both conventional DDR4 SDRAMs and Optane Memory (3D XPoint) modules, essentially supporting a hybrid memory subsystem. The new generation Intel Xeon Scalable processors, codenamed Sapphire Rapids, will also support HBM, so their hybrid memory subsystem will likely be similar to Apple's patented one.

The new MacBook Pro equipped with the new SoC M1 is also available on Amazon!