Which processor was the original Windows NT project targeted at?

The original Windows NT project was targeted at the Intel i860. Microsoft initially pursued the i860XR, an ambitious RISC processor, while designing an operating system intended to be portable across hardware platforms.

Development began in 1988–1989 under the name OS/2 3.0, during Microsoft’s collaboration with IBM. The i860-based Dazzle workstation served as an early development system. Microsoft later shifted work to the MIPS R3000 platform and then ported NT to Intel’s 80386 architecture, which became central to the first commercial release.

A common mix-up is confusing the original target with the processor families Windows NT supported at release. Windows NT 3.1 supported Intel x86, MIPS, and DEC Alpha systems, but those were not all the original development target. The i860 also helps explain the often-repeated claim that “NT” referred to the chip’s N10, or “N-Ten,” codename, although Microsoft later gave other explanations for the initials.