The
Cyrix Cx486SLC was
CyrixCyrix Corporation was a microprocessor developer that was founded in 1988 in Richardson, Texas as a specialist supplier of high-performance math coprocessors for 286 and 386 microprocessors. The company was founded by former Texas Instruments staff members and had a long but troubled relationship...
's first
CPUThe Central Processing Unit or processor is the portion of a computer system that carries out the instructions of a computer program, and is the primary element carrying out the computer's functions. This term has been in use in the computer industry at least since the early 1960s...
offering, released after years of selling
coprocessorA coprocessor is a computer processor used to supplement the functions of the primary processor . Operations performed by the coprocessor may be floating point arithmetic, graphics, signal processing, string processing, Savitsky-Golay derivation, or encryption. By offloading processor-intensive...
s that competed with Intel's units and offered better performance at a comparable or lower price.
The 486SLC is based on the i386SX bus, and was intended as an entry-level chip to compete with the Intel 386SX and 486SX.
Texas InstrumentsTexas Instruments , widely known as TI, is an American company based in Dallas, Texas, United States, renowned for developing and commercializing semiconductor and computer technology. TI is the No. 4 manufacturer of semiconductors worldwide after Intel, Samsung and Toshiba, and is the top supplier...
manufactured the 486SLC for Cyrix, and also sold it under its own name; ti486SLC.
The
Cyrix Cx486SLC was
CyrixCyrix Corporation was a microprocessor developer that was founded in 1988 in Richardson, Texas as a specialist supplier of high-performance math coprocessors for 286 and 386 microprocessors. The company was founded by former Texas Instruments staff members and had a long but troubled relationship...
's first
CPUThe Central Processing Unit or processor is the portion of a computer system that carries out the instructions of a computer program, and is the primary element carrying out the computer's functions. This term has been in use in the computer industry at least since the early 1960s...
offering, released after years of selling
coprocessorA coprocessor is a computer processor used to supplement the functions of the primary processor . Operations performed by the coprocessor may be floating point arithmetic, graphics, signal processing, string processing, Savitsky-Golay derivation, or encryption. By offloading processor-intensive...
s that competed with Intel's units and offered better performance at a comparable or lower price.
The 486SLC is based on the i386SX bus, and was intended as an entry-level chip to compete with the Intel 386SX and 486SX.
Texas InstrumentsTexas Instruments , widely known as TI, is an American company based in Dallas, Texas, United States, renowned for developing and commercializing semiconductor and computer technology. TI is the No. 4 manufacturer of semiconductors worldwide after Intel, Samsung and Toshiba, and is the top supplier...
manufactured the 486SLC for Cyrix, and also sold it under its own name; ti486SLC. Later, they also released their 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 (16-bit version of IBM 486DLC aka Blue Lightning) and
IBM 386SLCThe 386SLC was an Intel-licensed version of the 386SX , developed and manufactured by IBM in 1991. It included power-management capabilities and an 8KB internal cache, which meant it could run as fast as 386DX processors of the same speed, which were considerably more expensive...
are often confused with the Cyrix chips, but are not related and instead based on an Intel CPU core.
Introduced in May 1992, like the later and more famous
Cyrix Cx5x86Released in August 1995, four months before the more famous Cyrix 6x86, the Cyrix 5x86 was one of the fastest CPUs ever produced for Socket 3 computer systems...
it was a hybrid CPU, incorporating features of a new CPU (in this case the
Intel 80486The Intel i486 was the first tightly pipelined x86 design. Introduced in 1989, it was also the first x86 chip to use more than a million transistors, due to a large on-chip cache and an integrated floating point unit...
) while having a pin out similar to the existing 386SX, enabling existing board designs to be easily modified for the new chip. It ran at speeds of 20, 25, 33, and 40 MHz, although it had difficulty running reliably at 40 MHz using some operating systems. In December 1992 Cyrix also released the Cyrix Cx486SLC/e (25, 33 MHz) which offered power management, and a low voltage laptop version, the 3.3v Cyrix Cx486SLC/e-V (20, 25 MHz). In December 1993 Cyrix released a clock doubled version (25/50 MHz) cx486SLC2, as well as a clip-on upgrade for 386SX systems, the cx486SRx2 (16/33, 20/40 & 25/50 MHz).
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 24-bit address bus (16mb max. DRAM) , and 16-bit datapath which limited its memory bandwidth. Like the 386 and 486SX, it had no on-board math
coprocessorA coprocessor is a computer processor used to supplement the functions of the primary processor . Operations performed by the coprocessor may be floating point arithmetic, graphics, signal processing, string processing, Savitsky-Golay derivation, or encryption. By offloading processor-intensive...
, but unlike the 486SX, it could make use of an Intel 287, 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 when the latter was running on a full 32-bit bus.
The 486SLC was primarily used in very inexpensive low-end
motherboardA motherboard is the central printed circuit board in many modern computers, and holds many of the crucial components of the system, while providing connectors for other peripherals. The motherboard is sometimes alternatively known as the main board, system board, or, on Apple computers, the logic...
s and PC clones. Because of its low power consumption, it also saw use in
laptopA laptop is a personal computer designed for mobile use and small and light enough to sit on one's lap while in use. A laptop integrates most of the typical components of a desktop computer, including a display, a keyboard, a pointing device , speakers, and often including a battery, into a single...
s. The 486SLC was also available as a 32-bit version based on the i386DX bus, see 486DLC.