AI Vocabulary · 02 AI Infrastructure
What is CPU?
The central processor of every computer: a few strong, flexible cores that work through tasks one step after another.
A CPU, central processing unit, is the main processor in laptops, phones and servers. It has a small number of powerful cores that can run almost any program, jump between tasks and handle complicated logic quickly.
For AI, that flexibility is expensive. A neural network mostly repeats one simple operation, multiply and add, billions of times. A CPU works through these calculations with a few cores, while a GPU or another AI chip runs thousands of them at once. Computer architects John Hennessy and David Patterson describe how general processors now gain only a few percent of speed a year, which pushed the industry towards specialised chips.
Why it matters for you
Every AI system still needs CPUs: they run the operating system, prepare data and coordinate the specialised chips. A modern AI rack pairs its GPUs with CPUs. For small models, a fast CPU can even be enough to run AI on your own laptop.
Own it
Before you rent expensive GPU capacity, check whether your task really needs it. Classic data processing, simple automations and very small models often run well on CPUs at a fraction of the cost.
Where it comes from
The shift from general processors to specialised chips is explained in A New Golden Age for Computer Architecture by John Hennessy and David Patterson (Communications of the ACM, 2019).
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