I486SX

The i486SX was a microprocessor originally released by Intel in 1991. It was a modified Intel i486DX microprocessor with its floating-point unit (FPU) disabled. Priced at US$258, it was intended as a cheaper, lower-end option, denoted by the SX suffix, in line with the earlier i386SX. However, unlike the i386SX, which had a 16-bit external data bus and a 24-bit external address bus (compared to the fully 32-bit i386DX, its higher-end counterpart), the i486SX was entirely 32-bit.

The Intel486 SX-20 CPU can perform up 20 MIPS at 25 MHz, 70% faster than the 33 MHz Intel386 DX with external cache.