View source for Am486

{{Short description|80486-class computer processor family by AMD}}
{{more citations needed|date=May 2015}}
[[File:AMD Am486DX 40MHz 2007 03 27.jpg|thumb|AMD Am486DX 40 MHz]]
[[File:AMD Am486DX2 66MHz 2007 03 27.jpg|thumb|AMD Am486DX2 66MHz]]
[[File:AMD Am486 DX5 Am5x86-P75.jpg|thumb|AMD Am5x86-P75]]
[[File:AMD 80486DX2 die.jpg|thumb|AMD Am486 DX2-66 die shot]]
[[File:AMD 80486DX4 die.JPG|thumb|AMD Enhanced Am486 DX4-120 die shot]]
[[File:Nokia-9110-4.jpg|thumb|[[AMD Élan]] SC450 in [[Nokia 9110 Communicator]]]]

The '''Am486''' is a [[80486]]-class family of [[computer]] [[central processing unit|processors]] that was produced by [[AMD]] in the 1990s. [[Intel]] beat AMD to market by nearly four years, but AMD priced its 40&nbsp;MHz 486 at or below Intel's price for a 33&nbsp;MHz chip, offering about 20% better performance for the same price.

While competing 486 chips, such as those from [[Cyrix]], benchmarked lower than the equivalent Intel chip, AMD's 486 matched Intel's performance on a clock-for-clock basis.

While the [[Am386]] was primarily used by small computer manufacturers, the Am486DX, DX2, and SX2 chips gained acceptance among larger computer manufacturers, especially [[Acer Inc.|Acer]] and [[Compaq]], in the 1994 time frame.

AMD's higher clocked 486 chips provided superior integer performance to many of the early [[Pentium (original)|Pentium]] chips, especially the 60 and 66&nbsp;MHz launch products. While equivalent [[Intel 80486DX4]] chips were priced high and required a minor socket modification, AMD priced low. Intel's DX4 chips initially had twice the cache of the AMD chips, giving them a slight performance edge, but AMD's DX4-100 usually cost less than Intel's DX2-66.

The enhanced Am486 series supported new features like extended power-saving modes and an 8&nbsp;[[Kibibyte|KiB]] [[CPU cache#Details of operation|Write-Back]] [[CPU cache#Multi-level caches|L1-Cache]], later versions even got an upgrade to 16&nbsp;KiB Write-Back L1-Cache.

The 133&nbsp;MHz AMD [[Am5x86]] was a higher clocked enhanced Am486.

One derivative of the Am486 family is the core used in the [[AMD Élan]] SC4xx family of microcontrollers marketed by AMD.

== Features  ==
{{empty section|date=March 2023}}

==Am486 models==
[[Image:KL AMD 486SX2.jpg|thumb|Am486SX2-66.]]
[[Image:AMD 486DE2 66.jpg|thumb|Am486DE2-66 with power management for embedded systems.]]
{| class="wikitable"
! Model || [[Front-side bus|FSB]] || [[Clock rate|Clock speed]] || [[CPU core voltage|VCore]] || [[CPU cache#Multi-level caches|L1-Cache]] || Introduced
|-
| Am486 DX-25 || colspan="2" | 25&nbsp;MHz || rowspan="5" | 5 V || rowspan="15" | 8 [[Kibibyte|KiB]] WT ||
|-
| Am486 DX-33 || colspan="2" | 33&nbsp;MHz ||
|-
| Am486 DX-40 || colspan="2" | 40&nbsp;MHz || Apr 1993
|-
| Am486 SX-33 || colspan="2" | 33&nbsp;MHz ||
|-
| Am486 SX-40 || colspan="2" | 40&nbsp;MHz ||
|-
| Am486 DE2-66 || 33&nbsp;MHz || 66&nbsp;MHz || 3.3 V || 1996(?)
|-
| Am486 DX2-50 || 25&nbsp;MHz || 50&nbsp;MHz || 5 V || Apr 1993
|-
| Am486 DX2-66 || 33&nbsp;MHz || 66&nbsp;MHz || rowspan="2" | 5/3.3 V || Sep 1994<ref name="cpumuseum.jimdo.com">{{cite web |url=https://cpumuseum.jimdo.com/museum/amd/am486-5x86/ |title=Am486/5x86 |website=CPU MUSEUM |access-date=2017-07-19}}</ref>
|-
| Am486 DX2-80 || 40&nbsp;MHz || 80&nbsp;MHz || Sep 1994<ref name="cpumuseum.jimdo.com" />
|-
| Am486 SX2-50 || 25&nbsp;MHz || 50&nbsp;MHz || rowspan="2" | 5 V ||
|-
| Am486 SX2-66 || 33&nbsp;MHz || 66&nbsp;MHz || Apr 1994<ref name="cpumuseum.jimdo.com" />
|-
| Am486 DX4-75 || 25&nbsp;MHz || 75&nbsp;MHz || 3.3 V ||
|-
|Am486 DX4-90
|30&nbsp;MHz
|90&nbsp;MHz
|3.3 V
|
|-
| Am486 DX4-100 || 33&nbsp;MHz || 100&nbsp;MHz || 3.3 V || 1995
|-
| Am486 DX4-120 || 40&nbsp;MHz || 120&nbsp;MHz || 3.3 V ||
|-
| Enhanced Am486 DX2-66 || 33&nbsp;MHz || 66&nbsp;MHz || rowspan="5" | 3.3/3.45 V || 8/16 KiB WB ||
|-
| Enhanced Am486 DX2-80 || 40&nbsp;MHz || 80&nbsp;MHz || rowspan="2" | 8 KiB WB ||
|-
| Enhanced Am486 DX4-75 || 25&nbsp;MHz || 75&nbsp;MHz ||
|-
| Enhanced Am486 DX4-100 || 33&nbsp;MHz || 100&nbsp;MHz || rowspan="2" | 8/16 KiB WB ||
|-
| Enhanced Am486 DX4-120 || 40&nbsp;MHz || 120&nbsp;MHz ||
|}
'''WT''' = [[CPU cache#Details of operation|Write-Through cache strategy]], '''WB''' = [[CPU cache#Details of operation|Write-Back cache strategy]]

==References==
{{Reflist}}

== External links ==
{{Commons category}}
* {{webarchive |url=https://web.archive.org/web/20090423035409/http://www.amd.com:80/us-en/Processors/ProductInformation/0,,30_118_1260_1270,00.html |date=April 23, 2009 |title=AMD: Enhanced Am486 Microprocessors}}
* [http://www.digital-daily.com/editorial/amd-history/index02.htm AMD: 30 Years of Pursuing the Leader. Part 2]
* [http://www.cpu-collection.de/?tn=0&l0=co&l1=AMD&l2=486%20DX cpu-collection.de] AMD Am486 processor images and descriptions

{{AMD_processors}}

[[Category:AMD x86 microprocessors|Am486]]
[[Category:X86 microarchitectures]]
[[Category:Computer-related introductions in 1992]]