Cyrix Cx486SLC

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The Cyrix Cx486SLC was Cyrix's first CPU offering, released after years of selling coprocessors that competed with Intel's units and offered better performance at a comparable or lower price.

The 486SLC was intended as an entry-level chip to compete with the Intel 386SX and 486SX. Texas Instruments, who manufactured the 486SLC for Cyrix, also released its own version of the chip, the TI486SXLC which featured 8kB internal cache vs 1kB in the original Cyrix design. The similarly named IBM 486SLC, 486SLC2, 486SLC3 (pre-Blue Lightning) and IBM 386SLC chips were not related to the Cyrix design, however.

Introduced in May 1992, like the later and more famous Cyrix Cx5x86 it was a hybrid CPU, incorporating features of a new CPU (in this case the Intel 80486) while plugging into its predecessor's socket. It ran at speeds of 25, 33, and 40 MHz, although it had difficulty running reliably at 40 MHz using some operating systems.

The 486SLC can be described as a 386SX with the 486 instruction set and 1K of onboard L1 cache added. Unfortunately it inherited the 386SX's 16-bit bus and with it the limitation of 16 MB of RAM. Like the 386 and 486SX, it had no on-board math coprocessor, but unlike the 486SX, it could make use of an Intel 387sx or compatible coprocessor. Due to the limitations of the 386SX's bus and its smaller L1 cache, its performance could not compete with the 486SX.

Cyrix Cx486SLC/e is a low-power versions of Cx486SLC. Cx486SLC/e-V also featured low voltage (3.3V).

The 486SLC was primarily used in very inexpensive low-end motherboards and PC clones. Because of its low power consumption, it also saw use in laptops.