hardware//chip//MPU

A microprocessor unit (MPU) is a chip that contains only the core and its caches. The die has room for cache and nothing more, so it requires external RAM (heavy, DDR modules reached through a memory bus), storage such as ROM or an SSD (to save state) and peripheral chips on the PCB.

A microprocessor unit (MPU) is a chip that contains only the core and its caches. The die has room for cache and nothing more, so it requires external RAM (heavy, DDR modules reached through a memory bus), storage such as ROM or an SSD (to save state) and peripheral chips on the PCB.

Desktop and server processors (Intel Core, AMD Ryzen, Apple M-series) are MPUs, and modern ones are blurring into SoC territory by integrating GPU, NPU and memory controllers on the package.

One processor holds from 1 to 12 or more ARM cores (multi-core). Multicore is different from multiprocessor, which means several MPUs on one PCB.

Where the RAM sits depends on the platform. On iPhones it is stacked on the MPU package (tiny); Windows machines allow RAM upgrades, while Macs do not, because their RAM sits inside the MPU package.

An integrated GPU sits inside (the size of a fingernail, about 30 W, for lightweight inference), while a discrete GPU sits outside (the size of a hand, about 450 W, for heavy streams).