80487DX

The 80487DX, also known as the 487DX, was a math coprocessor designed by Intel for the Intel 80486DX microprocessor. It was released in 1991. The primary purpose of the 80487DX was to accelerate floating-point calculations, a task that was handled by the main CPU on earlier processors but was integrated into the 80486DX itself. However, Intel released the 80487DX as a separate upgrade for systems that shipped with an 80486DX socket but lacked an integrated math coprocessor, or for users who desired enhanced performance.

The 80487DX was essentially a full 80486DX processor with a built-in FPU, designed to coexist with the main 80486DX in certain motherboard configurations. When installed, the 80487DX would actually disable the main 80486DX CPU and take over its functions, effectively becoming the primary processor. This design allowed for a seamless upgrade path for users who had purchased 80486DX systems before integrated FPUs were standard. Early 80486DX processors did not have an integrated FPU. The 80487DX provided this functionality. It was available in various clock speeds, mirroring the speeds of the 80486DX processors it was designed to complement.