Editing I486 (section)

==Models==
Intel offered several suffixes and variants (see table). Variants include:
* ''[[RapidCAD|Intel RapidCAD]]'': a specially packaged Intel 486DX and a dummy [[floating-point unit]] (FPU) designed as pin-compatible replacements for an [[i386]] processor and [[Intel 80387|80387]] FPU.
* ''i486SL-NM'': i486SL based on i486SX.
* ''[[Intel 80487SX|i487SX (P23N)]]'': i486DX with one extra pin sold as an FPU upgrade to [[i486SX]] systems; When the i487SX was installed, it ensured that an i486SX was present on the [[motherboard]] but disabled it, taking over all of its functions.
* ''[[Intel 80486 OverDrive|i486 OverDrive (P23T/P24T)]]'': i486SX, i486SX2, i486DX2 or i486DX4. Marked as upgrade processors, some models had different pinouts or voltage-handling abilities from "standard" chips of the same speed. Fitted to a coprocessor or "OverDrive" socket on the motherboard, they worked the same as the i487SX.

The maximal internal clock frequency (on Intel's versions) ranged from 16 to 100&nbsp;MHz. The 16&nbsp;MHz i486SX model was used by [[Dell Computers]].

One of the few i486 models specified for a 50&nbsp;MHz bus (486DX-50) initially had overheating problems and was moved to the 0.8-[[Micrometre|micrometer]] fabrication process. However, problems continued when the 486DX-50 was installed in local-bus systems due to the high bus speed, making it unpopular with mainstream consumers. Local-bus video was considered a requirement at the time, though it remained popular with users of [[Extended Industry Standard Architecture|EISA]] systems. The 486DX-50 was soon eclipsed by the clock-doubled [[Intel 80486DX2|i486DX2]], which although running the internal CPU logic at twice the external bus speed (50&nbsp;MHz), was nevertheless slower because the external bus ran at only 25&nbsp;MHz. The i486DX2 at 66&nbsp;MHz (with 33&nbsp;MHz external bus) was faster than the 486DX-50, overall.

More powerful i486 iterations such as the OverDrive and [[DX4]] were less popular (the latter available as an OEM part only), as they came out after Intel had released the [[Pentium (original)|next-generation Pentium]] processor family. Certain steppings of the DX4 also officially supported 50&nbsp;MHz bus operation, but it was a seldom-used feature.

:{| class="wikitable"
! || Model || CPU/bus<br />clock speed || [[VCore|Voltage]] || [[L1 cache]]{{efn|1=''WT'' = write-through cache strategy, ''WB'' = write-back cache strategy.}} || Introduced 
! width="520px" | Notes
|-
| [[File:Intel i486 DX 25MHz SX328.jpg|80px]][[File:Intel i486 DX-33.jpg|80px]][[File:Intel i486 dx 50mhz 2007 03 27.jpg|80px]] || i486DX (P4) || 20, 25&nbsp;MHz<br />33&nbsp;MHz<br />50&nbsp;MHz || 5 V || 8&nbsp;KB WT || April 1989<br />May 1990<br />June 1991 || The original chip without clock multiplier
|-
| {{Anchor|486SL}}[[File:KL Intel 486SL.jpg|80px]] || i486SL || 20, 25, 33&nbsp;MHz || 5 V or 3.3 V || 8&nbsp;KB WT || November 1992 || Low-power version of the i486DX, reduced VCore, SMM ([[System Management Mode]]), stop clock, and power-saving features — mainly for use in portable computers
|-
| [[File:Intel i486 sx 33mhz 2007 03 27.jpg|80px]] || i486SX (P23) || 16, 20, 25&nbsp;MHz<br />33&nbsp;MHz || 5 V || 8&nbsp;KB WT || September 1991<br />September 1992 || An i486DX with the FPU part disabled; later versions had the FPU removed from the [[Integrated circuit|die]] to reduce area and hence cost.
|-
| [[File:Intel i486 dx2 66mhz 2007 03 27.jpg|80px]] || i486DX2 (P24) || 40/20, 50/25&nbsp;MHz<br />66/33&nbsp;MHz || 5 V || 8&nbsp;KB WT || March 1992<br />August 1992 || The internal processor clock runs at twice the [[clock rate]] of the external bus clock
|-
| || i486DX-S (P4S) || 33&nbsp;MHz; 50&nbsp;MHz || 5 V or 3.3 V || 8&nbsp;KB WT || June 1993 || SL Enhanced 486DX
|-
| [[File:KL Intel i486DX2 PQFP.jpg|80px]] || i486DX2-S (P24S) || 40/20&nbsp;MHz,<br />50/25&nbsp;MHz,<br />(''66/33&nbsp;MHz'') || 5 V or 3.3 V || 8&nbsp;KB WT || June 1993 || SL Enhanced 486DX2
|-
| [[File:KL Intel i486SX PQFP.jpg|80px]] || i486SX-S (P23S)|| 25, 33&nbsp;MHz || 5 V or 3.3 V || 8&nbsp;KB WT || June 1993 || SL Enhanced 486SX
|-
| [[File:KL intel i486SX2.jpg|80px]] || i486SX2 || 50/25, 66/33&nbsp;MHz || 5 V || 8&nbsp;KB WT || March 1994 || i486DX2 with the FPU disabled. Early version used the 800 nm process technology.<ref>Intel Corporation, "Coming Attractions: Clock-Doubling Technology", Microcomputer Solutions, January/February 1992, page 6.</ref>
|-
| [[File:FC80486DX4-75 AK SX883 USA 1995 01 WT.jpg|80px]][[File:Intel i486 DX4 100 MHz SK051.jpeg|80px]]|| IntelDX4 (P24C) || 75/25, 100/33&nbsp;MHz || 3.3 V || 16&nbsp;KB WT || March 1994 || Designed to run at triple clock rate (not quadruple, as often believed; the DX3, which was meant to run at 2.5× the clock speed, was never released). DX4 models that featured write-back cache were identified by an "&EW" laser-etched into their top surface, while the write-through models were identified by "&E". 
|-
| [[File:Intel i486 DX2 66 CPU SX955.jpg|80px]]|| i486DX2WB (P24D)|| 50/25&nbsp;MHz,<br />66/33&nbsp;MHz || 5 V || 8&nbsp;KB WB || October 1994 || Enabled write-back cache.
|-
| || i486DX2 (P24LM) || 90/30&nbsp;MHz,<br />100/33&nbsp;MHz || 2.5–2.9 V || 8&nbsp;KB WT || 1994 ||
|-
| [[File:Intel i486 dx4 100mhz 2007 03 27.jpg|80px]] || IntelDX4WB || 100/33&nbsp;MHz || 3.3 V || 16&nbsp;KB&nbsp;WB || 1995 ||Enabled write-back cache.
|-
| [[File:KL Intel i486GX.jpg|80px]]|| i486GX || up to 33&nbsp;MHz || 3.3 V || 8&nbsp;KB WT || || Embedded ultra-low-power CPU with all features of the i486SX and 16-bit external data bus. This CPU is for embedded battery-operated and hand-held applications.
|}
<!-- Should we specify what is meant by the slashes in this table?  Does 66/33&nbsp;MHz mean internal (doubled) clock 66&nbsp;MHz, external clock (oscillator and bus) 33&nbsp;MHz, as I think it does?  Why is i486DX2 (P24LM) listed with 30/90; 33/100 indicated in the reverse order?  Does inclusion of that last processor in this list imply something errant about the comment later that only AMD made the 90/30&nbsp;MHz grade? --Are the data in this table all Intel models, or are all other compatible processors included?  Either a title should be added showing this to be a table of Intel models only, or a "Manufacturer" column should be added, I think. -->
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