Intel changed the game in 1985 with the launch of its 386 CPU, ushering in the age of the 32-bit processor and paving the way for the lofty performance heights we take for granted today.
Originally released as the 80386 before being renamed as the i386, it was a third-generation x86 microprocessor, developed in collaboration with AMD and IBM.
The launch was a significant milestone for Intel, largely due to the poor reception of its predecessor, which Bill Gates famously described as “brain dead”.
Initially clocking in at speeds of 16 MHz – and eventually 33 MHz – the Intel 386 marked a step change for the company. First and foremost, it doubled the number of transistors compared to its predecessor to 275,000 while also boasting an on-chip memory management unit.
This powerful bit of kit could handle up to 4GB of memory, which for its time is impressive, and allowed for switching between three modes: ‘protected’ mode, ‘real’ mode, and ‘virtual’ mode.
The 386 proved a major hit globally, and quickly became the go-to CPU for an array of workstations and personal computers. In 1991, sales of the CPU accounted for around half of Intel’s total annual revenue, which may have been a relief given the company spent around $100 million developing the chip.
Its longevity is also a notable aspect of its success. While public use waned toward the end of the 1980s with the arrival of new processors, it still remained in use in embedded systems up until around 2007.
A deep dive into the make up of the 386
3D X-ray technology company, Lumafield, performed a CT scan on the chip on behalf of computer history blogger, Ken Shirriff. The resulting images give a fascinating glimpse into the make up of the CPU.
As Shirriff noted in a blog post, the scan produced hundreds of images that were eventually pulled together into a 3D model, allowing users to pull back the layers and see under the hood.
Starting with the package, Shirriff commented that this “provides no hint of the complex wiring embedded inside the ceramic”.
As the folks at Tom’s Hardware noted, it’s once you get deeper down that you see where the iconic chip’s power came from.
“It’s essentially a six-layer circuit board in miniature. Two internal layers carry the signals while four dedicated copper planes deliver clean, stable power and ground to different sections of the chip,” Hassam Nasir writes.
