IBM 386DX Processors

CPU-World — IBM 80386 Microprocessor Family (info & photos)
The New York Times — I.B.M. Making A 386 Chip
The UCA 386 Adapter now supports AMD & IBM 386s

Known Parts

The information presented here was provided by David Beem. Thanks!


IBM was helping Intel (and themselves, because it only alleviated Intel not needing to supply CPUs for some Model 70 and 80 systems) with the production of the 386DX processors — mostly at a time of the 20 and 25 MHz rated parts.

Because the CPU Reset Signatures match the Intel versions (including the only 0304h signature I have ever seen; I don't believe that Intel had identified that level in their datasheet information either), IBM likely used Intel's masks as-is.

Known Parts

23F7189CPUID 0304h (C Step)16 or 20 MHz?
51F1783likely a CPUID 0304h (C Step) or (Step D0)?16 or 20 MHz?
51F1784likely a CPUID 0305h (D0 Step)20 MHz
51F0352an unknown stepping20 MHz
32G3366an unknown stepping25 MHz
51F1797CPUID 0305h (D0 Step)25 MHz
63F7615CPUID 0305h (D0 Step)25 MHz

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Louis Ohland, Peter Wendt, David Beem, William Walsh, Tatsuo Sunagawa, Jim Shorney, Tim Clarke, Kevin Bowling, Tomáš Slavotínek, and many others.

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Last update: 30 Jul 2023 - Changelog | Legal Info & Contact