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 seri ...

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, and ...

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 to use

clock doubling 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 A phase-lock ...

, whereby the processor runs two internal logic clock cycles 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 fee ...

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 ope ...

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 be ...

calculations and the need for faster cache and more

memory bandwidth Memory bandwidth is the rate at which data can be read from or stored into a semiconductor memory by a central processing unit, processor. Memory bandwidth is usually expressed in units of bytes per second, bytes/second, though this can vary for ...

. Developers began to target the P5 Pentium processor family almost exclusively with x86 assembly language optimizations which led to the usage of terms such as '' Pentium compatible processor'' 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, which ...

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

AMD Advanced Micro Devices, Inc. (AMD) is an American multinational semiconductor company based in Santa Clara, California, that develops computer processors and related technologies for business and consumer markets. While it initially manufactur ...

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 19 ...

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 version).

External links

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

See also

External links