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Enhancing AI Accelerators with HBM3: Overcoming Memory Bottlenecks in the Age of Artificial Intelligence

High Bandwidth Memory 3 (HBM3): Overcoming Memory Bottlenecks in AI Accelerators

With the rise of generative AI models that can produce original text, picture, video, and audio material, artificial intelligence (AI) has made major strides in recent years. These models, like large language models (LLMs), were trained on enormous quantities of data and need a lot of processing power to function properly. However, because of their high cost and processing requirements, AI accelerators now require more effective memory solutions. High Bandwidth Memory, a memory standard that has various benefits over earlier memory technologies, is one such approach.        

How HBM is relevant to AI accelerators?

Constant memory constraints have grown problematic in a number of fields over the past few decades, including embedded technology, artificial intelligence, and the quick growth of generative AI. Since external memory interfaces have such a high demand for bandwidth, several programs have had trouble keeping up. An ASIC (application-specific integrated circuit) often connects with external memory, frequently DDR memory, through a printed circuit board with constrained interface capabilities. The interface with four channels only offers about 60 MB/s of bandwidth even with DDR4 memory. While DDR5 memory has improved in this area, the improvement in bandwidth is still just marginal and cannot keep up with the continuously expanding application needs.

However, a shorter link, more channels, and higher memory bandwidth become practical when we take the possibility of high memory bandwidth solutions into account. This makes it possible to have more stacks on each PCB, which would greatly enhance bandwidth. Significant advancements in high memory bandwidth have been made to suit the demands of many applications, notably those demanding complex AI and machine learning models.

The latest generation of High Bandwidth Memory

The most recent high bandwidth memory standard is HBM3, which is a memory specification for 3D stacked SDRAM that was made available by JEDEC in January 2022. With support for greater densities, faster operation, more banks, enhanced reliability, availability, and serviceability (RAS) features, a lower power interface, and a redesigned clocking architecture, it provides substantial advancements over the previous HBM2E standard (JESD235D). 

General Overview of DRAM Die Stack with Channels

[Source: HBM3 Standard [JEDEC JESD238A] Page 16 of 270]

P.S. You can refer to HBM3 Standard [JEDEC JESD238A]: https://www.jedec.org/sites/default/files/docs/JESD238A.pdf for further studies.   

How does HBM3 address memory bottlenecks in AI accelerators?

HBM3 is intended to offer great bandwidth while consuming little energy, making it perfect for AI tasks that need quick and effective data access. HBM3 has a number of significant enhancements over earlier memory standards, including:

Increased bandwidth

Since HBM3 has a substantially larger bandwidth than its forerunners, data may be sent between the memory and the GPU or CPU more quickly. For AI tasks that require processing massive volumes of data in real time, this additional bandwidth is essential.

Lower power consumption

Since HBM3 is intended to be more power-efficient than earlier memory technologies, it will enable AI accelerators to use less energy overall. This is crucial because it may result in considerable cost savings and environmental advantages for data centers that host large-scale AI hardware.

Higher memory capacity

Greater memory capacities supported by HBM3 enable AI accelerators to store and analyze more data concurrently. This is crucial for difficult AI jobs that need access to a lot of data, such as computer vision or natural language processing.

Improved thermal performance

AI accelerators are less likely to overheat because to elements in the architecture of HBM3 that aid in heat dissipation. Particularly during demanding AI workloads, this is essential for preserving the system’s performance and dependability.

Compatibility with existing systems

Manufacturers of AI accelerators will find it simpler to implement the new technology because HBM3 is designed to be backward-compatible with earlier HBM iterations without making substantial changes to their current systems. This guarantees an easy switch to HBM3 and makes it possible for quicker integration into the AI ecosystem.

In a word, HBM3 offers enhanced bandwidth, reduced power consumption, better memory capacity, improved thermal performance, and compatibility with current systems, making it a suitable memory choice for AI accelerators. HBM3 will play a significant role in overcoming memory constraints and allowing more effective and potent AI systems as AI workloads continue to increase in complexity and size.

Intellectual property trends for HBM3 in AI Accelerators

HBM3 in AI Accelerators is witnessing rapid growth in patent filing trends across the globe. Over the past few years, the number of patent applications almost getting doubled every two years.    

MICRON is a dominant player in the market with 50% patents. It now holds twice as many patents as Samsung and SK Hynix combined. Performance, capacity, and power efficiency in today’s AI data centers are three areas where Micron’s HBM3 Gen2 “breaks new records.” It is obvious that the goal is to enable faster infrastructure utilization for AI inference, lower training periods for big language models like GPT-4, and better total cost of ownership (TCO).       

Other key players who have filed for patents in High bandwidth memory technology with are Intel, Qualcomm, Fujitsu etc.   

key players who have filed for patents in High bandwidth memory

[Source: https://www.lens.org/lens/search/patent/list?q=stacked%20memory%20%2B%20artificial%20intelligence]  

Following are the trends of publication and their legal status over time:

Legal status for patent applications and documents

[Source: https://www.lens.org/lens/search/patent/list?q=stacked%20memory%20%2B%20artificial%20intelligence]

These Top companies own around 60% of total patents related to UFS. The below diagram shows these companies have built strong IPMoats in US jurisdiction.  

IPMoats in US jurisdiction

[Source: https://www.lens.org/lens/search/patent/list?q=stacked%20memory%20%2B%20artificial%20intelligence]

Conclusion

In summary, compared to earlier memory standards, HBM3 provides larger storage capacity, better bandwidth, reduced power consumption, and improved signal integrity. HBM3 is essential for overcoming memory limitations in the context of AI accelerators and allowing more effective and high-performance AI applications. HBM3 will probably become a typical component in the next AI accelerator designs as the need for AI and ML continues to rise, spurring even more improvements in AI technology.    

Meta Data

The performance of AI accelerators will be improved by the cutting-edge memory technology HBM3, which provides unparalleled data speed and efficiency.

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Computer Science

High Bandwidth Memory (HBM3) Products | SK Hynix | Samsung | Nvidia and related IEEE Papers

High Bandwidth Memory (HBM3)

JEDEC has released HBM3 with the JESD238A standard. It offers multiple advantages over previous releases of HBM technology in terms of speed, latency, and computational capabilities. The HBM3 technology implements RAS architecture for reducing memory error rates.

Second Generation of HBM implements 2.4 Gb/s/pin with 307-346 GB/s. Further, HBM2E implements 5.0 Gb/s/pin with 640 Gb/s, and third Generation of HBM implements 8.0 Gb/s/pin with 1024 GB/s.

A table describing about comparison of HBM2, HBM2E, And HBM3:

We have tried collecting all available information on the internet related to the HBM3 memory system. The blog includes documents of different versions of standards, related products, and IEEE Papers from manufacturers.

Different HBM standards released by JEDEC

Multiple version of the HBM memory system and their links are:

HBM1: JESD235: (Oct 2013): https://www.jedec.org/sites/default/files/docs/JESD235.pdf 
HBM2: JESD235A: (Nov 2015): https://web.archive.org/web/20220514151205/https://composter.com.ua/documents/JESD235A.pdf
HBM2E: JESD235B: (Nov 2018): not available
HBM2 Update: JESD235C: (Jan 2020): not available
HBM1, HBM2: JESD235D: : (Feb 2021): https://www.jedec.org/sites/default/files/docs/JESD235D.pdf
HBM3: JESD238: (Jan 2022): not available
HBM3 update: JESD238A: (Jan 2023): https://www.jedec.org/sites/default/files/docs/JESD238A.pdf

HBM1: 

JEDEC released the first version of the HBM standard, named HBM1 (JESD235 standard), in October 2013, and its link is below:

https://www.jedec.org/sites/default/files/docs/JESD235.pdf

HBM2:

JEDEC released the second version of the HBM standard, named HBM2 (JESD235A standard), in November 2015, and its link is below:

https://web.archive.org/web/20220514151205/https://composter.com.ua/documents/JESD235A.pdf

Further, JEDEC released the third version of the HBM standard named HBM2E (JESD235B standard) in November 2018 and HBM2 Updation (JESD235C) in January 2020. The link is not available on the internet.

HBM3:

JEDEC released a new version of the HBM standard named HBM3 (JESD238A standard) on Jan 2023, and its link is

https://www.jedec.org/sites/default/files/docs/JESD238A.pdf

Multiple new Features introduced in HBM3 are:

New features introduced in HBM3 for increasing memory speed and reducing memory latency are:

  1. On-Die DRAM ECC Operation
  2. Automated on-die error scrubbing mechanism (Error Check and Scrub (ECS) operation)
  3. MBIST enhanced memory built-in self-test (MBIST)
  4. WDQS Interval Oscillator
  5. Duty Cycle Adjuster (DCA) | Duty Cycle Monitor (DCM)
  6. Self-Repair Mechanism


Different IEEE Papers from other manufacturers are available. Manufacturers are working on HBM3 memory standard JEDEC JESD238A for various memory operations. They are implementing a new mechanism introduced in the HBM3 standard.

Samsung and SK Hynix are significant manufacturers of HBM3 and have revealed many research papers stating or indicating their implementation of different features of HBM3. The paper describes how various implemented technical features are introduced in the HBM3 memory system.

Products implementing HBM3 technology:

Products implementing HBM3 technology

SAMSUNG HBM3 ICEBOLT:

The memory system stacks 12 stacks of DRAM memory systems for AI operations. It provides processing speeds up to 6.4Gbps and bandwidth that reaches 819GB/s.

SAMSUNG HBM3 ICEBOLT
Fig 1. Samsung HBM3 ICEBOLT variants

Link to this product: https://semiconductor.samsung.com/dram/hbm/hbm3-icebolt/

SKHYNIX HBM3 memory system:

SKhynix announces 12 layers of HBM3 with 24 GB memory capacity

Fig 2. SK Hynix HBM3 24 GB memory system

Link to this product: https://news.skhynix.com/sk-hynix-develops-industrys-first-12-layer-hbm3/

Nvidia Hopper H100 GPU implementing HBM3 memory system:

Nvidia Hopper H100 GPU implementing HBM3 memory system
Fig 3. Nvidia Hopper H100 GPU implementing HBM3 memory system

IEEE Papers from different Manufacturers exploring HBM3 technology

IEEE papers and their links from Samsung, SK Hynix, and Nvidia are mentioned. These papers are written authors from Samsung, SK Hynix, and Nvidia. The authors are exploring different technological aspects of the HBM3 memory system. The IEEE paper shows the architecture of the HBM memory system and various features:

Samsung IEEE paper related to HBM3:

Samsung has been working on HBM3 technology and has already released multiple products about it.

IEEE Paper1:

Title: A 4nm 1.15TB/s HBM3 Interface with Resistor-Tuned Offset-Calibration and In-Situ Margin-Detection
DOI10.1109/ISSCC42615.2023.10067736
Link: https://ieeexplore.ieee.org/document/10067736

IEEE Paper2:

Title: A 16 GB 1024 GB/s HBM3 DRAM with On-Die Error Control Scheme for Enhanced RAS Features
DOI10.1109/VLSITechnologyandCir46769.2022.9830391
Link: https://ieeexplore.ieee.org/document/9830391

IEEE Paper3:

Title: A 16 GB 1024 GB/s HBM3 DRAM With Source-Synchronized Bus Design and On-Die Error Control Scheme for Enhanced RAS Features
DOI10.1109/JSSC.2022.3232096
Link: https://ieeexplore.ieee.org/document/10005600

Samsung HBM3 Architecture
Fig 4. Samsung HBM3 architecture

Data-bus architecture of HBM2E and HBM3
Fig 5. Data-bus architecture of HBM2E and HBM3

SK Hynix IEEE paper related to HBM3:

SK Hynix has also published 2 IEEE papers describing the HBM3 memory technological aspect.

IEEE Paper 1 and IEEE Paper 2 of SK Hynix:

IEEE Paper1:

Title: A 192-Gb 12-High 896-GB/s HBM3 DRAM With a TSV Auto-Calibration Scheme and Machine-Learning-Based Layout Optimization|
DOI: 10.1109/ISSCC42614.2022.9731562
Link: https://ieeexplore.ieee.org/document/9731562

IEEE Paper2:

Title: A 192-Gb 12-High 896-GB/s HBM3 DRAM With a TSV Auto-Calibration Scheme and Machine-Learning-Based Layout Optimization
DOI: 10.23919/VLSIC.2019.8778082
Link: https://ieeexplore.ieee.org/document/8778082/

SK Hynix architecture of HBM3 memory system
Fig 6. SK Hynix architecture of HBM3 memory system.

Nvidia IEEE paper related to HBM3:

Nvidia has also published 1 IEEE paper about the HBM3 memory system. The paper describes that Hopper H100 GPU is implementing five HBM memory systems with a total memory bandwidth of over 3TB/s.

IEEE Paper1:

Title: NVIDIA Hopper H100 GPU: Scaling Performance
DOI10.1109/ISSCC42614.2022.9731562
Link: https://ieeexplore.ieee.org/abstract/document/10070122

Nvidia Hopper H100 implementing HBM3 memory system
Fig 7. Nvidia Hopper H100 implementing HBM3 memory system.

TSMC IEEE paper related to HBM3:

TSMC has also published 1 IEEE paper pertaining to the HBM3 memory system. The paper implements integrated de-cap capacitors for suppressing power domain noise and for enhancing the HBM3 signal integrity at a high data rate.

IEEE Paper1:

Title: Heterogeneous and Chiplet Integration Using Organic Interposer (CoWoS-R)
DOI10.1109/ISSCC42614.2022.9731562
Link: https://ieeexplore.ieee.org/document/10019517/

HBM and Chiplet side of a system
Fig 8. HBM and Chiplet side of a system

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Electronics

Understanding Hidden Markov Model in Natural Language – Decoding Amazon Alexa

Alexa is a cloud-based software program that acts as a voice-controlled virtual personal assistant. Alexa works by listening for voice commands, translating them into text, interpreting the text to carry out corresponding functions, and delivering results in the form of audio, video, or device/accessory triggers.

Hidden Markov Models (HMMs) are a type of probability model that can be used in Natural Language Understanding (NLU) to help programs come to the most likely decision based on both previous decisions and observations.

Machine learning plays a critical role in improving Alexa’s ability to understand and respond to voice commands over time.

Alexa has three main parts: Wake word, Invocation name, and Utterance. Here is a breakdown of each part:

  • Wake word: This is the word that users say to activate Alexa. By default, the wake word is “Alexa,” but users can change it to “Echo,” “Amazon,” or “Computer.
  • Invocation name: This is the unique name that identifies a custom skill. Users can invoke a custom skill by saying the wake word followed by the invocation name. The invocation name must not contain the wake words “Alexa,” “Amazon,” “Echo,” or the words “skill” or “app.
  • Utterance: This is the spoken phrase that users say to interact with Alexa. Users can include additional words around their utterances, and Alexa will try to understand the intent behind the words.
Natural Language Processing (NLP)

What is NLP?

Natural Language Processing (NLP) is a key component of Alexa’s functionality. NLP is a branch of computer science that involves the analysis of human language in speech and text. It is the technology that allows machines to understand and interact with human speech, but is not limited to voice interactions. NLP is the reader that takes the language created by Natural Language Generation (NLG) and consumes it. Advances in NLP technology have allowed dramatic growth in intelligent personal assistants such as Alexa.

Alexa uses NLP to process requests or commands through a machine learning technique. When a user speaks to Alexa, the audio is sent to Amazon’s servers to be analysed more efficiently. To convert the audio into text, Alexa analyses characteristics of the user’s speech such as frequency and pitch to give feature values. The Alexa Voice Service then processes the response and identifies the user’s intent, making a web service request to a third-party server if needed.

In summary, NLP is the technology that allows Alexa to understand and interact with human speech. It is used to process requests or commands through a machine learning technique, and NLU is a key component of Alexa’s functionality that allows it to infer what a user is asking for when they ask a question in a variety of ways.

Hidden Markov Model (NLU Example) 

Hidden Markov Model (NLU Example) 

HMMs are used in Alexa’s NLU to help understand the meaning behind the words spoken by the user. Here is an example of how HMMs can be used in Alexa’s NLU:

  1. The user says “Alexa, play some music.”
  2. The audio is sent to Amazon’s servers to be analyzed more efficiently.
  3. The audio is converted into text using speech-to-text conversion.
  4. The text is analyzed using an HMM to determine the user’s intent. The HMM takes into account the previous decisions made by the user, such as previous music requests, as well as the current observation, which is the user’s request to play music.
  5. Alexa identifies the user’s intent as “play music” and performs the requested action.

Conclusion

In summary, Alexa’s NLP architecture involves converting the user’s spoken words into text, processing the text to identify the user’s intent, and performing complex operations such NLU using the Alexa Voice Service.