Path: utzoo!attcan!uunet!cbmvax!daveh
From: daveh@cbmvax.UUCP (Dave Haynie)
Newsgroups: comp.arch
Subject: Re: 68020 vs. 68030 speed (was Re: 80486 vs. 68040 code size)
Message-ID: <6922@cbmvax.UUCP>
Date: 19 May 89 04:33:39 GMT
References: <13804@steinmetz.ge.com>
Distribution: eunet,world
Organization: Commodore Technology, West Chester, PA
Lines: 29

in article <13804@steinmetz.ge.com>, davidsen@sungod.steinmetz (William Davidsen) says:

> Given any particular architecture, using a 16 bit o/s like MS-DOS, there
> will be very little performance diference between the 286 and 386.

In fact, some 286 instructions go faster on the 286 than the 386 pertending
to be a 286.

> However, if the 386 code uses the full instruction set, it should run
> much faster than a 286 at the same speed, running the best 16 bit
> version of the same program. Of course there can be programs written to
> always use 16 bit data, so this is not an absolute.

Well, certainly, if you've got something that needs lots of data memory, like
Compress, you're goofy to run this on a '286 machine, with all those
silly "far" pointer routines.  Can't help but go faster when it's recompiled
for any 32 bit machine.

Conversely, little tiny programs (eg, Benchmarks) can find themselves sitting
completely in an external 32k cache such as one finds on many high end '386
machines.  One may find these programs run much faster launched from MS-DOS,
and thus owning the machine, than were they run under UNIX, where a task swap
may come along and dump the cache....

> 	bill davidsen		(davidsen@crdos1.crd.GE.COM)
-- 
Dave Haynie  "The 32 Bit Guy"     Commodore-Amiga  "The Crew That Never Rests"
   {uunet|pyramid|rutgers}!cbmvax!daveh      PLINK: D-DAVE H     BIX: hazy
              Amiga -- It's not just a job, it's an obsession