// central processing unit

The CPU:
From kHz to GHz

Five decades of clock speed, transistor density, and the multicore revolution — the processor that built the modern world.

2,300
Transistors, Intel 4004 (1971)
184B
Transistors, Apple M3 Ultra (2025)
6.2GHz
Peak clock speed today
// transistor growth

This page charts CPU transistor count history from the Intel 4004's 2,300 transistors (1971) to the Apple M3 Ultra's 184 billion (2025) — alongside clock speed growth and the multicore revolution. Use the interactive charts to explore how and why CPU development evolved over five decades.

CPU Transistor Count, 1971–2025

Moore's LawGordon Moore (Intel co-founder) observed in 1965 that the number of transistors on a chip doubles approximately every two years. It became the industry's de facto roadmap for 50 years. predicted transistor counts would double every two years. For five decades, the industry delivered — until around 2016, when transistors became so small that quantum effectsAt sizes below ~7nm, electrons can "tunnel" through barriers they shouldn't be able to cross, causing leakage current and heat. This makes transistors unreliable and power-hungry at very small scales. The industry's response: 3D stacking, chiplets, and new materials like Gate-All-Around (GAA) transistors instead of simply shrinking further. like electron leakage made further shrinking increasingly difficult.

CPU Transistor Count over Time
// logarithmic scale · highest transistor count per generation · data: Wikipedia, Karl Rupp, Intel, Apple
// performance metrics

Clock Speed & Core Count

Clock speedClock speed (measured in GHz) is how many cycles a processor executes per second. After 2004, rapid scaling hit a thermal wall — chips couldn't be pushed faster without melting. Growth continued, but slowly: from ~4 GHz in 2013 to 6.2 GHz by 2024, compared to the near-doubling every two years before 2004. growth slowed sharply after 2004 due to thermal limits. The industry's response: more coresA core is an independent processing unit within a chip. A 4-core CPU can handle 4 tasks simultaneously. Modern chips have up to 24+ cores for consumers. More cores = better multitasking and parallel workloads, but only if software is written to use them.. Today both strategies run in parallel — clocks creep up while core counts continue to grow.

The Strategic Shift: Clock Speed vs. Core Count
// x86 desktop processors · clock growth slows ~2004, cores accelerate — both strategies run in parallel · data: Intel, AMD, Wikipedia
// key milestones

CPU History Timeline

The processors that defined each era.

1971
Intel 4004
The world's first commercially produced microprocessor. 4-bit, 740 kHz, 2,300 transistors.
1993
Intel Pentium
3.1 million transistors, 60 MHz. Defined the PC era and became a household name.
2006
Intel Core 2 Duo
The multicore revolution arrives on the desktop. Two cores become the new normal.
2020
Apple M1
16 billion transistors. Apple's first ARM chip for Mac — outperforms Intel laptops at a fraction of the power draw. ARM architecture goes mainstream.
2017
AMD Ryzen
After years of Intel dominance, Ryzen's Zen architecture restored genuine x86 competition. 8 cores at mainstream prices forced Intel to accelerate its own core counts.
2025
Apple M3 Ultra
184 billion transistors — the highest count in any consumer CPU as of March 2025. Dual-die design via Apple's UltraFusion interconnect. Up to 512 GB unified memory.
// frequently asked

Common Questions

The Apple M3 Ultra has 184 billion transistors, built on TSMC's 3nm process using a dual-die UltraFusion design with up to 512 GB unified memory. As of early 2025, the M3 Ultra held this record. Apple skipped an M4 Ultra entirely; an M5 Ultra has not yet been released as of March 2026.
After 2004, rapid scaling hit a thermal wall — chips could not be pushed faster without melting. Growth continued slowly, from around 4 GHz in 2013 to 6.2 GHz by 2024, compared to the near-doubling every two years before.
The Intel 4004 (1971), the world's first commercially produced microprocessor, had 2,300 transistors and ran at 740 kHz.
The multicore era began around 2006 with processors like the Intel Core 2 Duo. After clock speed scaling hit a thermal wall, the industry responded by adding more cores — a 4-core CPU can handle 4 tasks simultaneously.