What's inside Intel Pentium Pro Processor chip

The Intel Pentium Pro processor, released in 1995, was a significant advancement in its time. While its technology might seem outdated compared to modern CPUs, understanding its internal components can offer valuable insights into the evolution of processor design. Here's a breakdown of what was inside a Pentium Pro chip

Central Processing Unit (CPU) Die

Execution Units: The Pentium Pro had six execution units: two integer units, one floating-point unit (FPU), a load unit, store address unit, and a store data unit. These units handled different processing tasks like calculations, data movement, and memory access.

Cache: It incorporated two levels of cache:

L1 cache: 8 or 16 Kilobyte (separate for data and instructions) stored frequently used data close to the execution units for faster access.

L2 cache: Located on a separate die, it offered a larger capacity of 256 Kilobyte, 512 Kilobyte, or even 1megabyte  further reducing main memory access latency.

Microprocessor Core: Built on a 0.50 micrometer or 0.35 micrometer BiCMOS process, it housed the transistors and logic circuits responsible for core processing tasks.

Package

Ceramic Multi-Chip Module (MCM): The Pentium Pro wasn't a single chip but two dies housed in a ceramic MCM. One die held the CPU core, and the other contained the L2 cache.

Socket: It used Socket 8, a specific connector interface compatible with motherboards designed for this processor.

Front-Side Bus: This bus connected the processor to the main memory and chipset, operating at 60 or 66 MHz for data transfer.

Clock Crystal: Regulated the internal operating frequency of the processor, typically ranging from 150 to 200 MHz.

Voltage Regulator: Provided the necessary power to various components within the chip.

Overall, the Pentium Pro was a complex and powerful processor for its time, featuring multiple execution units, large L2 cache, and BiCMOS technology. While its internal design wouldn't compare to modern multi-core processors, understanding its components gives us a glimpse into the fascinating journey of processor evolution.