Intel 486 DX

Historia

The 486 is very similar to its predecessor, the 386. Main differences are an optimised instruction set, an on-chip unified instruction and data cache, an optional on-chip floating-point unit (FPU), and an enhanced bus interface unit. These improvements yield a rough doubling in performance over an 386 at the same clock rate. There are several suffixes and variants including: 486SX - 486 with its FPU disabled 486DX - 486 with a working FPU 486DX-2 - runs at twice the external clock rate 486SL - 486DX with power conservation circuitry 486SL-NM - 486SX with power conservation circuitry 487 - 486DX with slightly different pinout for use in 486SX systems as FPU OverDrive - 486DX-2 with slightly different pinout for use in 486SX systems RapidCAD - 486DX in a special package with a companion FPU dummy package for use in 386 systems 486DLC - mix version by some manufacturers, featuring a 486 instruction set and a 386-compatible pinout The 486 processor has been licensed or reverse engineered by other companies such as IBM, AMD and Cyrix. Some manufacturers made hybrid 386/486 CPUs (Cxrix Cx486DLC, Texas Instruments TX486DLC), having a 486 instruction set and a 386-compatible pinout.