[Thread] A look at the first ARM processor ARM1, which was built in 1985 and had 25K transistors, next to Apple's M1 chip, which has 8 cores and 16B transistors
how it started: how it's going: https://twitter.com/...
@kenshirriffKen Shirriff
Context & Ripple Effects
Ken Shirriff's die-shot comparison lands three days after Apple announced the M1 as its first Apple-silicon SoC for Macs — a chip with 16 billion transistors against the 25,000 of the 1985 ARM1 he dissects. The pairing is pointed: the architecture Apple just bet its Mac line on is the same one that began as a low-power Acorn processor.
The thread also closes a loop that started with Kuo's early-2020 prediction of an ARM-based Mac within 12–18 months, and it foreshadows what Mercury Research would later quantify: ARM's PC-chip share roughly quadrupling once M1 Macs went on sale.
First-order effects
Intel is out of the Mac lineup entirely as of the M1 launch, and AnandTech's Mac mini testing shows the fan-cooled chip already besting Intel parts and matching AMD's Zen 3 — so the transition's performance risk resolved in Apple's favor almost immediately.
Second-order effects
Rival PC chipmakers face a new benchmark: Apple's vertical integration lets it tune silicon, OS, and software together, forcing Intel and AMD to compete on perf-per-watt rather than peak clocks — the axis where the M1's results were strongest.
Third-order effects
If Mercury Research's trajectory holds, the x86 duopoly in PCs gives way to a two-architecture market, with ARM's share gains driven by one vertically integrated customer rather than by ARM licensees broadly — a structural change in how PC silicon gets designed and sold.
The trend: Personal computing is shifting from x86 incumbency toward ARM-based, vertically integrated system-on-chip designs, with Apple's M1 as the proof point and the 35-year-old ARM1 as its origin.
Here are the two dies at the same scale. The M1 is over twice as large physically as the ARM1. It has 16 billion transistors vs 25,000 for the ARM1. If you built the ARM1 using the same technology, it would be a pixel-sized speck. https://twitter.com/...
@kenshirriff
Ken Shirriff on x
The ARM1 had an 84-pin package, 30mm wide. The M1 package is smaller at ~21mm wide, and has DRAM modules on it. Compare the yellow ceramic disc decoupling capacitors on the ARM1 board with the tiny 0402 capacitors surrounding the M1 die. (Photo shows packages at same scale.) http…
The ARM processor started with the Acorn RISC Machine project in 1983. Apple got involved in the late 1980s, using the low-power ARM 610 processor in the ill-fated Newton handheld. In 1990, Acorn, Apple, and VLSI Technology formed Advanced RISC Machines, with Apple owning 43%.
@kenshirriff
Ken Shirriff on x
Looking at the ARM1 die, you see functional blocks such as 100 bytes of registers and a basic 32-bit ALU. On the M1 die, similar-sized functional blocks are a 12-megabyte cache and a complete 64-bit CPU core. It shows what Moore's law has done over 35 years. https://twitter.com/.…
@kenshirriff
Ken Shirriff on x
With Apple's recent announcement of the ARM-based M1 processor, I figured it would be interesting to compare it to the first ARM processor, created by Acorn Computers in 1985 for the BBC Micro computer. Designers were Sophie Wilson and Steve Furber.
@dangrabham
Dan Grabham on x
It's absolutely nuts that Acorn's work on the BBC Micro and Archimedes would end up being the foundation of most Apple devices in the 2020s. https://twitter.com/...
@natbullard
Nat Bullard on x
A really superb thread on 35 years of processor development by @kenshirriff. I love this: “If you built the [1985] ARM1 using the same technology [as the 2020 M1] would be a pixel-sized speck.” https://twitter.com/...
@kenshirriff
Ken Shirriff on x
The ARM1 processor ran at 6 megahertz, while the M1 runs at 3.2 gigahertz, over 500 times faster. While the ARM1 was a single processor, the M1 has 4 high-performance CPU cores, 4 efficiency CPU cores, a 16-core neural engine, and 8-core GPU.
@kenshirriff
Ken Shirriff on x
To see the ARM1 in action with its 25,000 transistors blinking away, check out the simulator created by the Visual 6502 team: https://visual6502.org/...
@walkingrandomly
Mike Croucher on x
I had an Archimedes back in the day. A3010. 2Mb RAM , a 1.6Mb floppy drive and no hard disk. Built in BBC Basic and bright green function keys. ARM250 processor OMG I loved that machine! https://twitter.com/...
@dcominottim
@dcominottim on x
I absolutely love the mindshare Apple's M1 & Arm are getting. The knowledgeable can scream all they want at the marketing, but if they were *wise*, they'd realize the effects prove Apple's marketing did a textbook move. And, thankfully, their narrative has obsoleted “MOAR CORES.”
@choco_bit
Fudge on x
There's a lot of jumping to conclusions with those M1 benchmarks atm and it's kinda sad. Wait a week or 2 for proper real world based tests to come out and don't rely on worthless ones like geekbench