The

Intel Intel Corporation is an American multinational corporation and technology company headquartered in Santa Clara, California. It is the world's largest semiconductor chip manufacturer by revenue, and is one of the developers of the x86 ser ...

i486DX2, rumored as 80486DX2 (later renamed IntelDX2) is a

CPU A central processing unit (CPU), also called a central processor, main processor or just processor, is the electronic circuitry that executes instructions comprising a computer program. The CPU performs basic arithmetic, logic, controlling, a ...

produced by

that was first introduced in 1992. The i486DX2 was nearly identical to the i486DX, but it had additional

clock multiplier In computing, the clock multiplier (or CPU multiplier or bus/core ratio) sets the ratio of an internal CPU clock rate to the externally supplied clock. A CPU with a 10x multiplier will thus see 10 internal cycles (produced by PLL-based frequency ...

circuitry. It was the first

chip Chromatin immunoprecipitation (ChIP) is a type of immunoprecipitation experimental technique used to investigate the interaction between proteins and DNA in the cell. It aims to determine whether specific proteins are associated with specific genom ...

to use clock doubling, whereby the processor runs two internal logic

clock cycle In electronics and especially synchronous digital circuits, a clock signal (historically also known as ''logic beat'') oscillates between a high and a low state and is used like a metronome to coordinate actions of digital circuits. A clock sig ...

s per external bus cycle. An i486 DX2 was thus significantly faster than an i486 DX at the same bus speed thanks to the 8K on-chip cache shadowing the slower clocked external bus. The i486DX2-66 was a very popular processor for

video game Video games, also known as computer games, are electronic games that involves interaction with a user interface or input device such as a joystick, controller, keyboard, or motion sensing device to generate visual feedback. This feedba ...

s enthusiasts in the early to mid-90s. Often coupled with 4 to 8 MB of RAM and a VLB video card, this CPU was capable of playing virtually every game title available for years after its release, right up to the end of the

MS-DOS MS-DOS ( ; acronym for Microsoft Disk Operating System, also known as Microsoft DOS) is an operating system for x86-based personal computers mostly developed by Microsoft. Collectively, MS-DOS, its rebranding as IBM PC DOS, and a few o ...

game era, making it a "sweet spot" in terms of CPU performance and longevity. The introduction of 3D graphics spelled the end of the 486's reign, because of their heavy use of

floating point In computing, floating-point arithmetic (FP) is arithmetic that represents real numbers approximately, using an integer with a fixed precision, called the significand, scaled by an integer exponent of a fixed base. For example, 12.345 can ...

calculations and the need for faster

cache Cache, caching, or caché may refer to: Places United States * Cache, Idaho, an unincorporated community * Cache, Illinois, an unincorporated community * Cache, Oklahoma, a city in Comanche County * Cache, Utah, Cache County, Utah * Cache County ...

and more memory bandwidth. Developers began to target the P5

Pentium Pentium is a brand used for a series of x86 architecture-compatible microprocessors produced by Intel. The original Pentium processor from which the brand took its name was first released on March 22, 1993. After that, the Pentium II and P ...

processor family almost exclusively with

x86 assembly language x86 assembly language is the name for the family of assembly languages which provide some level of backward compatibility with CPUs back to the Intel 8008 microprocessor, which was launched in April 1972. It is used to produce object code for t ...

optimizations which led to the usage of terms such as ''

Pentium compatible processor The Pentium (also referred to as P5, its microarchitecture, or i586) is a fifth generation, 32-bit x86 microprocessor that was introduced by Intel on March 22, 1993, as the very first CPU in the Pentium brand. It was instruction set compatible ...

'' for software requirements. An i486DX2-50 version was also available, but because the bus speed was 25 MHz rather than 33 MHz, this was a significantly less popular processor. There are two major versions of the DX2 - Identified by P24 and P24D, the latter has a faster

L1 cache A CPU cache is a hardware cache used by the central processing unit (CPU) of a computer to reduce the average cost (time or energy) to access data from the main memory. A cache is a smaller, faster memory, located closer to a processor core, whic ...

mode, called "

write-back In computing, a cache ( ) is a hardware or software component that stores data so that future requests for that data can be served faster; the data stored in a cache might be the result of an earlier computation or a copy of data stored elsewhe ...

", that improves performance. The original P24 version offered only the slower "write-through" cache mode. AMD and

Cyrix Cyrix Corporation was a microprocessor developer that was founded in 1988 in Richardson, Texas, as a specialist supplier of floating point units for 286 and 386 microprocessors. The company was founded by Tom Brightman and Jerry Rogers. In ...

both produced a competitor for the Intel i486DX2. File:Intel 80486DX2 top.jpg, An Intel i486DX2-66 Microprocessor, top view. File:Intel 80486DX2 bottom.jpg, The bottom view with gold plated pins visible. File:KL Intel i486DX2 PQFP.jpg, Embedded i486DX2 (SL enhanced,

SQFP A quad flat package (QFP) is a surface-mounted integrated circuit package with "gull wing" leads extending from each of the four sides. Socketing such packages is rare and through-hole mounting is not possible. Versions ranging from 32 to 304 ...

version).

External links

Intel Datasheets
Embedded i486DX2
DX2 {{microcompu-stub de:Intel i486#i486DX2

See also

External links