Gaming and Competitive alternatives

Gaming

The 486DX2 66 MHz was the most widespread high-end 486 version.[citation needed]? For many players of video games during the early and mid 1990s, towards the end of the MS-DOS gaming era, it was often coupled with 8 - 16 MB RAM and a VLB video card. This configuration was capable of running every title[citation needed] available for several years after its release, making it a "sweet spot" in CPU performance and longevity. The introduction of 3D computer graphics spelled the end of the 486's reign, because 3D graphics make heavy use of floating point calculations and the need for faster CPU cache and more memory bandwidth. Developers also began to target the Pentium almost exclusively with x86 assembly language optimizations (e.g. Quake); many of these games required the speed of the Pentium's double-pipelined architecture anyway, so even if the code had been optimized for the 486 instead, it still would not have given satisfactory performance there.

Competitive alternatives

486 compatible processors have been produced by other companies such as IBM, Texas Instruments, AMD, Cyrix, UMC, and SGS Thompson. Some are near duplicates in terms of specifications and performance, some are not. (IBM had a requirement that parts in its machines be available from multiple sources; this may explain the IBM versions.) The 486 was, however, covered by many of Intel's patents relating to the 80386 as well as some of its own. Intel and IBM have broad cross-licenses of these patents, and AMD was granted rights to the relevant patents in the 1995 settlement of a lawsuit between the companies

AMD produced several models of the 486 using a 40 MHz bus (486DX-40, 486DX/2-80 & 486DX/4-120) which had no equivalent available from Intel, as well as a 90 MHz part using a proprietary 30 MHz external clock sold only to OEMs[citation needed]This sentence was somewhat mangled, not sure if the present interpretation about the 30 MHz is correct.. The fastest running 486 CPU, the Am5x86, ran at 133 MHz was released by AMD in 1995. 150 MHz and 160 MHz parts were planned but never officially released.