Definition
Plain language
The main chip in your computer that does most of the general-purpose work.
As stated in the literature
Central Processing Unit — the general-purpose processor handling most program logic, distinct from a GPU which specializes in parallel workloads.
Why it matters: Knowing what runs on CPU versus GPU governs nearly every performance and cost decision in modern ML systems.
For example, the CPU handles your operating system, browser logic, and most everyday apps, while the GPU sits idle until you launch a game or AI workload.
Heard on the show
“Because it all runs as bookkeeping on the CPU and never touches the GPU.”Episode 165 — A Free-Lunch Tweak That Lets a Tiny Agent Beat Frontier Giants