NPU vs TPU: The Future of AI Hardware Explained

Craig Adebanji
6 min readDec 14, 2023

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How NPUs are revolutionizing smartphone AI and machine learning

Artificial intelligence (AI) is transforming the world in unprecedented ways. From self-driving cars to smart assistants, AI applications are becoming more common and powerful. But how does AI work behind the scenes? What kind of hardware does it need to run efficiently and effectively?

In this article, we will compare two types of AI hardware: neural processing units (NPUs) and tensor processing units (TPUs). We will explain what they are, how they differ, and how they compare in terms of performance, cost, and availability. By the end of this article, you will have a better understanding of the future of AI hardware and its implications for society.

What are NPUs and TPUs?

Neural processing units (NPUs) are specialized chips that are designed to accelerate the processing of neural networks. Neural networks are a type of AI that mimic the structure and function of the human brain. They consist of layers of interconnected nodes, called neurons, that process and transmit information. NPUs are optimized to perform the mathematical operations that are involved in neural network processing, such as matrix multiplication and convolution. NPUs can be integrated into CPUs, GPUs, or ASICs, or they can be standalone chips.

Tensor processing units (TPUs) are also specialized chips that are designed to accelerate the processing of neural networks. However, unlike NPUs, TPUs are not based on the traditional von Neumann architecture, which separates the memory and the processing units. Instead, TPUs use a novel architecture, called systolic array, which integrates the memory and the processing units into a single chip. This allows TPUs to perform parallel computations faster and more efficiently than NPUs.

TPUs are developed by Google and are only available on the Google Cloud Platform or the Google Pixel phones. They have different versions and generations, such as TPU v1, TPU v2, TPU v3, and TPU v4. Some of the features of TPUs are:

Tensor Core: It is the main component of a TPU that performs matrix multiplications and convolutions. These are the core operations of deep learning. It can process large amounts of data in parallel and with high precision.

TensorFlow: It is the main software framework that is used to program and run deep learning models on TPUs. It is an open-source library that provides various tools and functions for building and deploying machine learning applications.

TensorBoard: It is a visualization tool that is used to monitor and debug deep-learning models on TPUs. It can display various metrics and graphs, such as accuracy, loss, gradients, weights, and activations.

NPU vs TPU

How do NPUs and TPUs differ?

NPUs and TPUs differ in several aspects, such as:

Architecture:

NPUs use the traditional von Neumann architecture, which separates the memory and the processing units. TPUs use the systolic array architecture, which integrates the memory and the processing units into a single chip.

Performance:

NPUs have a higher peak performance than TPUs, but they also have a higher latency and power consumption. TPUs have a lower peak performance than NPUs, but they also have a lower latency and power consumption.

Cost:

NPUs are more expensive than TPUs, because they require more components and more complex designs. TPUs are cheaper than NPUs, because they require fewer components and simpler designs.

Availability:

NPUs are more widely available than TPUs, because they are produced by many companies, such as Intel, Nvidia, Huawei, and Samsung. TPUs are less widely available than NPUs, because they are produced by only one company, Google.

How do NPUs and TPUs compare?

To compare NPUs and TPUs, we can look at some benchmarks that measure their performance in different tasks, such as image recognition, natural language processing, and speech synthesis. Here are some examples of benchmarks and their results:

ImageNet:

ImageNet is a large dataset of images that are classified into 1000 categories. The task is to train a neural network to recognize the category of a given image. The results show that NPUs have a higher accuracy than TPUs, but they also take longer to train and consume more power.

BERT:

BERT is a large neural network that is trained to understand natural language. The task is to fine-tune BERT for various natural language processing tasks, such as question answering, sentiment analysis, and text summarization. The results show that TPUs have a higher accuracy than NPUs, and they also take less time to train and consume less power.

Tacotron 2:

Tacotron 2 is a neural network that is trained to synthesize speech from text. The task is to generate natural-sounding speech from a given text. The results show that TPUs have a higher quality than NPUs, and they also take less time to generate and consume less power.

What are the advantages and disadvantages of NPUs and TPUs?

Based on the comparison above, we can summarize the advantages and disadvantages of NPUs and TPUs as follows:

NPUs:

NPUs have the advantage of having a higher peak performance than TPUs, which means they can handle more complex and diverse neural networks. However, NPUs also have the disadvantage of having a higher latency and power consumption than TPUs, which means they are slower and more costly to run.

TPUs:

TPUs have the advantage of having a lower latency and power consumption than NPUs, which means they are faster and more efficient to run. However, TPUs also have the disadvantage of having a lower peak performance than NPUs, which means they can handle only specific and optimized neural networks.

What are the current and future applications of NPUs and TPUs?

NPUs and TPUs have many current and future applications in various domains, such as:

Cloud computing:

NPUs and TPUs can be used to provide cloud-based AI services, such as image recognition, natural language processing, and speech synthesis. For example, Google Cloud offers TPU-based AI services, such as Cloud Vision, Cloud Natural Language, and Cloud Text-to-Speech.

Edge computing:

NPUs and TPUs can be used to enable edge-based AI applications, such as face recognition, voice control, and gesture recognition. For example, Huawei's Kirin 990 chip integrates an NPU that can power edge-based AI applications on smartphones and other devices.

Autonomous vehicles:

NPUs and TPUs can be used to support autonomous driving systems, such as object detection, lane detection, and path planning. For example, Tesla's Full Self-Driving chip uses an NPU that can process 2300 frames per second and support 12 cameras and 8 radars.

Healthcare:

NPUs and TPUs can be used to enhance healthcare services, such as diagnosis, treatment, and monitoring. For example, Google's Health TPU can help detect diseases, such as diabetic retinopathy and breast cancer, from medical images.

In conclusion, NPUs and TPUs are two types of AI hardware that are designed to accelerate the processing of neural networks. They differ in their architecture, performance, cost, and availability. They also have their own advantages and disadvantages, depending on the task and the context. They have many current and future applications in various domains, such as cloud computing, edge computing, autonomous vehicles, and healthcare.

AI hardware is an exciting and evolving field that has a huge impact on society. As NPUs and TPUs become more advanced and accessible, we can expect to see more innovations and opportunities in AI.

What do you think about NPUs and TPUs? Which one do you prefer and why? Let me know in the comments below.

Reference:

https://inquisitiveuniverse.com/2023/12/05/npu-vs-tpu-what-are-they-and-how-they-compare/

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