What Is an NPU? The AI Chip in Your Laptop and Phone Explained

An NPU, short for neural processing unit, is a small processor built to run the math behind AI models using far less power than a general-purpose chip. If you have bought a phone or laptop in the last few years, there is a good chance one is already inside it.

For what these chips let phones do offline, see our separate explainer on on-device phone AI and privacy.

What is an NPU, in one paragraph?

According to Wikipedia's entry on neural processing units, an NPU is a specialized hardware accelerator for artificial intelligence and machine learning workloads such as neural networks and computer vision. It can be a standalone chip or a block inside a CPU or GPU.

On consumer devices the same entry describes NPUs as meant to be small, power-efficient and reasonably fast when running small models. An NPU is a low-power helper for jobs like background blur on a video call, live captions, photo cleanup and voice recognition.

How is an NPU different from a CPU and a GPU?

A CPU (central processing unit) is the general-purpose brain. It handles the operating system, your apps and any task that involves lots of branching decisions. It can run AI math, but it is not built around it.

A GPU (graphics processing unit) does huge numbers of simple calculations in parallel, which is why it became the standard engine for AI in data centers. Wikipedia notes that GPUs typically run AI workloads through existing general-purpose pipelines such as CUDA and OpenCL, adapted for lower precision.

An NPU narrows the design further. Wikipedia describes NPU designs as often "manycore" or "spatial," with an emphasis on low-precision arithmetic, new dataflow layouts or in-memory computing. Low precision means storing numbers with fewer bits, such as 8-bit integers (INT8) or even 4-bit (INT4), which is cheaper in energy and good enough for many AI models.

The gap is shrinking, since the same source points out that modern GPUs now include dedicated units for low-precision matrix multiplication too. In a modern laptop the three processors often share the work, and the software decides which one gets each task.

What does TOPS mean, and does a bigger number mean a faster NPU?

TOPS stands for trillions of operations per second. A chip rated at 40 TOPS can, at its theoretical peak, perform 40 trillion basic operations each second. Wikipedia adds that the metric does not specify the type of operation, which is typically INT8 additions and multiplications.

That is why TOPS is a weak shopping tool. Intel's Robert Hallock, the company's VP of AI and Technical Marketing, called it "kind of a goofy metric" and a theoretical peak, as reported by Laptop Mag. He argued that peak figures have some value but do not show how well hardware performs in practice.

A TOPS rating leaves out what decides real-world speed:

• Memory speed, because a model's weights have to be fed to the chip fast enough.
• Software support, because an app must be written to use the NPU at all.
• Precision, since a TOPS figure quoted at INT8 is not comparable to one quoted at a different number format.
• Heat and battery limits, which cap how long a chip can hold its peak.

Which NPUs actually exist? Apple, Qualcomm, Intel and AMD

Apple Neural Engine. Apple's announcement of the M4 chip says its Neural Engine is capable of "38 trillion operations per second," which Apple calls 60x faster than the first Neural Engine in A11 Bionic. Wikipedia dates Apple's AI accelerators in its silicon to around 2017, which lines up with the A11.

Qualcomm Hexagon. Qualcomm's launch specifications for the Snapdragon X Elite list a Hexagon NPU rated at 45 TOPS, as summarized by Gigazine. Notebookcheck reports that this is a theoretical figure that applies to all Snapdragon X versions.

Intel. Intel's Lunar Lake generation includes an NPU rated at up to 48 TOPS. Laptop Mag reports that Intel counted the whole platform at up to 120 TOPS, made up of 48 on the NPU, 67 on the GPU and 5 on the CPU, and that Intel was still finalizing those numbers when it spoke. The earlier Meteor Lake chips carried an Intel-built VPU (versatile processing unit) for inference, per Wikipedia.

AMD. AMD's NPU sits inside its Ryzen AI chips and is built on the XDNA architecture. Coverage of the Ryzen AI 300 launch, such as this Laptop Mag comparison, puts its XDNA 2 NPU at up to 50 TOPS.

All of these are vendor peak ratings. Different companies measure them under their own conditions, so a 45 versus 48 versus 50 difference says very little about which laptop will feel faster.

Why does 40 TOPS keep showing up on laptop boxes?

Microsoft set it as a floor. According to TweakTown's report, a PC needs an NPU of at least 40 TOPS to qualify as a Copilot+ PC. Neowin reports that Microsoft also requires 16 GB of RAM and 256 GB of fast storage for those machines.

The threshold explains why the numbers across Qualcomm, Intel and AMD cluster just above 40. It also means the badge tells you only that the NPU clears a bar. Coverage of the requirement also notes that 40 TOPS is plenty for lightweight tasks such as live captions and webcam effects, but is not enough on its own to run a large language model locally at a pleasant speed. Check Microsoft's own page for the current requirements, since this was reported at launch in 2024.

Do you need an NPU, or will the GPU do?

For most people the answer is that you will get one whether you ask or not. NPUs are now built into mainstream chips, so the real question is whether the software you use takes advantage of it.

The efficiency argument is the NPU's strongest card: a dedicated block can do small, constant AI jobs without waking the power-hungry GPU. But Intel's own executive said an NPU alone is not enough for AI workloads, and Laptop Mag reports that Intel's 2025 roadmap assumed a split of about 30% NPU, 40% GPU and 30% CPU. Even the company selling the NPU expects the GPU to do the largest share.

If you are buying a laptop, an NPU is a reasonable tiebreaker but a poor main reason. Memory, battery life and the apps you run matter more. If you are buying specifically to run large local models, GPU power and memory capacity are likely to matter more than the NPU's TOPS label. For how Apple's current chips compare, see our MacBook Pro M6 vs M5 upgrade guide.

What to watch next

Whether everyday software beyond Microsoft's own features targets NPUs is the first test of their value. Vendors also face pressure to move to more comparable measurements than a single peak number, since even Intel's AI chief doubts TOPS. The split of work between NPU, GPU and CPU will keep shifting as models grow.

Each vendor also keeps raising its ratings. Qualcomm's own product page now lists higher figures for its newer X2 chips, which makes the 45 TOPS first-generation number a moving target. Before you trust any new rating, look for independent testing of real tasks, and for the precision and conditions behind the figure.