Apple Patent May Hint at the Future of Its Chips: A Multi-Level Hybrid Memory Subsystem

Apple has patented a hybrid reminiscence subsystem that incorporates at least two varieties of reminiscence: a high-bandwidth low-density sort of DRAM in addition to a low-bandwidth high-density sort of DRAM. The patent might supply a glimpse of how Apple sees the long run of its system-on-chips. Naturally, the new patent will gas hypothesis that shall we see more moderen variations of Apple’s M1 chip include the new reminiscence design, however this sort of implementation may well be utilized in a number of differing types of chips.

Patents do not all the time manifest as merchandise on the marketplace, however given the comments now we have won from patent attorney Kerry Creeron, it seems that that Apple has long gone to nice pains, and expense, to patent this new methodology in a big selection of jurisdictions round the international, implying that it may well be utilized in Apple’s merchandise international. 

New System Architecture Requires New Memory Architecture

Apple’s transfer to its M1 SoCs from Intel’s CPUs and AMD’s discrete GPUs is vital no longer handiest as a result of the corporate is transitioning from x86 CPUs to Arm, and from Radeon CPUs to a PowerVR-derived structure, however as it considerably adjustments the formula structure of its PCs. 

CPUs and discrete GPUs have their very own reminiscence subsystems, while SoCs in most cases depend on a unified reminiscence structure. UMA has a large number of benefits over devoted reminiscence subsystems, but it surely additionally has one necessary drawback, too: in an UMA formula, the CPU and GPU need to proportion reminiscence ability and bandwidth, one thing that can have an effect on efficiency in sure situations.  

(Image credit score: Apple)

HBM2 and HBM2E varieties of reminiscence supply very excessive bandwidth, however those reminiscence gadgets value so much, eat so much, and can’t be upgraded via the end-user. In distinction, construction a high-capacity reminiscence subsystem with sufficient bandwidth for a high-end GPU the use of standard or GDDR-type reminiscence is not all the time imaginable, or possible. In a bid to mix the perfect of each worlds, Apple has patented a hybrid reminiscence subsystem combining HBM-like and DDR-like varieties of DRAM. 

Apple’s patent entitled “reminiscence formula having mixed excessive density, low bandwidth and occasional density, excessive bandwidth reminiscences” describes quite a lot of SoCs that use high-bandwidth cache DRAM in addition to high-capacity major DRAM. The patent covers strictly system-on-chips and no longer PCs, so all DRAMs are meant to be soldered down onto the substrate or onto the mainboard, identical to the LPDDR4X chips that Apple makes use of on its M1 SoC. The structure described on this very patent signifies that Apple does not envision utilization of usual reminiscence modules, at least with some of its hybrid reminiscence subsystems. 

“With two varieties of DRAM forming the reminiscence formula, one of that could be optimized for bandwidth and the different of that could be optimized for ability, the objectives of bandwidth building up and ability building up might each be learned, in some embodiments,” an outline via Apple reads. “[Some implementations of hybrid memory subsystems may] to enforce power potency enhancements, which might supply a extremely power environment friendly reminiscence answer that also is excessive efficiency and excessive bandwidth.” 

(Image credit score: Apple)

Since Apple is a notebook-centric PC maker, it’s not unexpected that it’s that specialize in the power efficiencies equipped via hybrid reminiscence subsystems. Meanwhile, it’s obtrusive that the different benefits come with extra efficiency and ability.  

The patent most commonly covers quite a lot of bodily implementations of a number of hybrid reminiscence subsystems comprised of cache DRAM and major DRAM interconnected the use of a large number of applied sciences. For instance, one format comprises through-silicon vias (TSVs) that go via a stack of major DRAM reminiscence chips, which permits putting in a quite important quantity of DRAM ability whilst no longer the use of so much of house. Meanwhile, the patent does not quilt how working techniques or device may just take merit of a hybrid reminiscence subsystem.

(Image credit score: Apple)

An Important Technology

Apple, identical to another high-tech corporate, recordsdata packages for masses of patents yearly. Some of the patent packages develop into actual merchandise, however others don’t. But Apple’s patent application US10573368B2 used to be filed in 2021, after which the corporate filed suitable packages in lots of jurisdictions throughout the international, which signifies that the structure is predicted for use international (i.e., in lots of Apple merchandise).  


(Image credit score: Apple)

“This patent used to be filed in a big selection of jurisdictions, together with the EP (European Patent Org.), U.S., China, and Japan,” mentioned Kerry Creeron, an lawyer with the company of Banner & Witcoff. “Such a large submitting technique is pricey and normally handiest is sensible if IP coverage is necessary.” 

Another attention-grabbing factor to notice about the patent is the title of one of the inventors; Sukalpa Biswa moved to Apple from PA Semi, so he will have to have so much of revel in with CPU design.

Not An Apple Exclusive

Apple’s hybrid reminiscence subsystems without a doubt glance very spectacular, however it is not going that this sort of hybrid era will likely be unique to Apple. 


(Image credit score: Apple)

Intel’s fashionable Xeon Scalable processors can paintings each with standard DDR4 SDRAM in addition to Optane Memory (three-D XPoint) modules, necessarily supporting a hybrid reminiscence subsystem. Intel’s next-generation Xeon Scalable codenamed Sapphire Rapids processor may also make stronger HBM, so its hybrid reminiscence subsystem will most probably appear to be the one Apple has patented.