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Correction of RE: PC 80486 ** CORRECTION **

Ashok Aiyar ashok at biochemistry.cwru.edu
Thu Jan 28 22:21:01 EST 1993


In article <C34907EFA03058B2 at uclaue.mbi.ucla.edu> DULANEY at UCLAUE.MBI.UCLA.EDU writes:

>    I pulled a couple of magazines off my shelf just to make sure that this 
>is correct. (PC Magazine V11 N17 p115-257 and PC World December 1991 p 148-
>167) Neither was the definative article that I remember reading somewhere 
>but both contain sidebars about the 486SX.  Perhaps Ken was thinking of the 
>Cyrix 486SLC, which is essentially a 386SX (16-bit data path) with a 1K 
>cache and psuedoFPU.  Whoops, this is longer than I intended.  
>     Bottom line. 486SX= 486DX - FPU. 32 bits internally and externally.

Correct.  All CPUs in the *Intel* 486 series, including the 486SX, 486DX, 
486DX2, OverDrive Processor are 32 bits internally and externally.  

The Cyrix 486 SLC is basically a 386SX with a 1K internal cache, and is 
386SX pin compatible -- i.e 16 bit external bus.

The Cyrix 486 DLC is 386DX pin compatible, making it 32 bits internally and 
externally.  Neither Cyrix CPU has an internal FPU.

Cyrix reputedly has double-clocked versions of its 486 processors on the 
cards.

Ashok

Follow-ups to: comp.sys.ibm.pc.hardware
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                              Ashok Aiyar 
                      Department of Biochemistry
                       CWRU School of Medicine
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