The
Cyrix Cx486DLC was an early 486 CPU from
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...
, intended to compete with the Intel 486SX and DX.
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...
, who manufactured the 486DLC for Cyrix, later released its own version of the chip, the TI486SXL with 8kB internal cache vs 1kB of the original Cyrix design. The similarly named IBM 486DLC, 486DLC2, 486DLC3 (aka Blue Lightning) are often confused with the Cyrix chips, but are not related and instead based on Intel's i486 design.
Introduced in June 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 plugging into its predecessor's (386DX) socket.
The
Cyrix Cx486DLC was an early 486 CPU from
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...
, intended to compete with the Intel 486SX and DX.
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...
, who manufactured the 486DLC for Cyrix, later released its own version of the chip, the TI486SXL with 8kB internal cache vs 1kB of the original Cyrix design. The similarly named IBM 486DLC, 486DLC2, 486DLC3 (aka Blue Lightning) are often confused with the Cyrix chips, but are not related and instead based on Intel's i486 design.
Introduced in June 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 plugging into its predecessor's (386DX) socket. It ran at speeds of 25, 33, and 40 MHz.
The 486DLC can be described as a 386DX with the 486 instruction set and 1K of onboard L1 cache added. Because it used the 386DX bus (unlike its 16-bit cousin, the 486SLC) it was a fully
32-bitThe range of integer values that can be stored in 32 bits is 0 through 4,294,967,295 or −2,147,483,648 through 2,147,483,647 using two's complement encoding...
chip. 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 387DX or compatible numeric coprocessor. A few 486SX motherboards also provided i387 sockets, but this feature was a very much a rarity. Due to its slower 386 bus and the smaller L1 cache, the 486DLC could not compete on a clock-for-clock basis with the 486SX, but a 33MHz 486DLC could keep pace with a 25 MHz 486SX, cost less, and offered the ability to upgrade further with the addition of an inexpensive math coprocessor.
While some advertisements in PC magazines from smaller manufacturers touted the superiority of their 486DLC over name-brand computers sporting a 486SX, in reality the only advantage the 486DLC offered feature-wise over the 486SX was the ability to add an inexpensive math-coprocessor. The Intel 487 "math coprocessor" for 486SX users was in reality a CPU replacement—a 486DX with a different pinout—and originally cost several hundred dollars more than a 387.
As prices on Intel's 486 line fell, Cyrix found it more and more difficult for its 486SLC and DLC CPUs to compete and had to release a fully pin-compatible version of the 486SX and DX in 1993.
The 486DLC did not see widespread use among large OEMs, but it was widely known among the hardware enthusiast community that an
AMD 386DX-40The Am386 CPU was released by AMD in 1991. A 100%-compatible clone of the Intel 80386 design, it sold millions of units and positioned AMD as a legitimate competitor to Intel, rather than just a second source for x86 CPUs ....
or Cyrix 486DLC-33 could keep up with a 486SX-25 at a lower cost, so it gained a small following among budget-minded enthusiasts. It was also sometimes used as a replacement for a 386 CPU to give a small speed boost. However, the 486DLC was not designed to be a direct CPU replacement and could lead to stability problems in older boards it was not intended for. Cyrix later released a clock-doubled "direct replacement" upgrade chip for 386DX systems called the Cx486DRx2.