PC80486

penniston at MAYO.EDU penniston at MAYO.EDU
Mon Jan 25 15:00:15 EST 1993


!In article <1993Jan25.090410.12066 at gserv1.dl.ac.uk>, 
!schnorr at tournesol.versailles.inra.fr (Kirk Schnorr) writes:
!|> I was wondering if anyone out there could inform me about the relative
!|> differences between the various flavors of 486 CPU chips in PC
!|> computers.  We are about to buy a new system for data aquisition and
!|> proccessing for our HPLC to replace our slow and failing HP Vectra 286.
!|> 	We were thinking to get a 486SX based machine since it is the
!|> cheapest but I do not want to sacrifice a built in  math co-proccessor
!|> or 32 bit data path it the 486SX is missing these.  Can anyone enlighten
!|> me?

!My understanding of the various members of the Intel 80386 and 80486 families 
!are as follows:
!
!Chip		Internal	External	Floating
!Designation	Data Path	Data Path	Point Unit?
!-----------	---------	---------	-----------
!386DX		32 bits		32 bits		No
!386SX		32 bits		16 bits		No
!
!486DX		32 bits		32 bits		Yes
!486SX		32 bits		16 bits		Yes
!
!Please note that Intel uses the "SX" designation to denote the narrower 
!external data path, NOT the presence or absence of a math coprocessor.


	I don't think this is quite right, since Intel has used their chip
names in a rather confusing way recently.  As I understand it, the correct
table should read as follows:

Chip		Internal	External	Floating
Designation	Data Path	Data Path	Point Unit?
-----------	---------	---------	-----------
386DX		32 bits		32 bits		No
386SX		32 bits		16 bits		No

486DX		32 bits		32 bits		Yes
486SX		32 bits		32 bits		No

	As you can see, Intel changed the meaning of "SX" between the 386
and 486 chips.

			John Penniston
			Biochem. & Mol. Biol.
			Mayo Clinic
			Penniston at mayo.edu





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