Roger L.
Hughes Lans Systems
Mountain View, CA
`Underneath your clothes you are naked!'
I'm not too sure about the 486sx, (ie. I'm assuming that's the one
without the math coprocessor), but since it has a 16 bit data bus
rather than a 32 bit data bus, its probably slower than I think.
Anyway, generally for a 386 and 486 at the same speed, the 486 will
run at least twice as fast, since most of the instructions are
optimized to run in a single clock-cycle, while on the 386, they run
in 2 or 3. Those which take more clock cycles are either equivalent,
or longer by a few clock cycles on the 386. The 486 has a few extra
instructions built-in. And you're looking at about the same speed.
You'll either be getting a very fast 386, or a superslow 486. So you
gotta decide what you'd prefer.
SuperDave
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The opinions expressed are not mine, nor anyone's.
Why ask magazine-level questions when you can read the managazine just like
we did? And why answer a magazine question when you can't remember the
article you read anymore?? The 486dx is a real 486 that didn't make it
through 486 boot-camp, but still fondly remembers its 486 chip-school
training, except the trig, which was forcibly removed by sales-droids,
and was too hard anyway. No math coprocessor, yes a full 32 (THIRTY-TWO)
bit data path. Which is better depends on whether you are DOS (386/40)
or UNIX (toss-up, since 486* machines do better with 32-bit instructions).
Of course, all this is just something I infer from what I read in some
magazine, so get out your salt-shakers on this one.
Well.......
From what i've read, the pinouts on the 486sx are slightly different
than on the 486dx...
Undoubtedly a ploy for Intel to then catch you in the next scam.... The
487sx! The 487sx is actually just a 486dx... plugs into the
'coprocessor' slot on the 486sx boards and actually DISABLES the entire
486sx processor...
If I'm wrong about this, let me know....
But.... it seems like a typical Intel SCAM...
Todd J. Derr
University of Pittsburgh...
Yup, the pin-outs of the 486DX, 486SX and 487SX are all slightly different,
so the chips are not plug compatible.
>Undoubtedly a ploy for Intel to then catch you in the next scam.... The
>487sx! The 487sx is actually just a 486dx... plugs into the
>'coprocessor' slot on the 486sx boards and actually DISABLES the entire
>486sx processor...
Again, this is true. Placing a 487SX into a 486SX machine will in fact
turn off the 486SX. The 487SX does everything. However, note that the
socket is not a *coprocessor* socket. It's supposed to be called "the
performance upgrade socket." (Yeah, yeah, I know -- we're pushing it.)
The idea is that at some later time, there might be something else to
plug into it than just a 487SX.
>If I'm wrong about this, let me know....
>
>But.... it seems like a typical Intel SCAM...
Well, since I work for Intel, I better not comment on whether I think
it's a scam. Although, I do have my opinion about it...
Wolf
=> Wolf Witt, Design Engineer <=> You say there is a bug in this chip? <=
=> i860 Focus Group, Intel Corp. <=> No, no, you don't understand... <=
=> ww...@smdvx1.intel.com <=> This is a feature! <=
=> Intel knows nothing about what I say or do, but they pay me anyway. <=
This is the subject of the cover story in June 1991 Byte magazine.
Sorry, SuperDave, you don't know what you're talking about.
The 486sx has a full 32-bit bus, what it's missing is the
math coprocessor only. (and it runs at 20 MHz)
For the original question, one important factor is if you
need a math coprocessor and what it will cost. At one point,
Intel was asking about $800 for the 487sx.
--
A place for everything and everything in its place.
The 486SX is a 32 bit machine. You are confusing it with the 386SX.
Danny Low
"Question Authority and the Authorities will question You"
Valley of Hearts Delight, Silicon Valley
HP NPCD dl...@pollux.svale.hp.com
You're completely right, of course...
However several makers have come out with a
compromise.. you get what is essentially a
backplane with a plug-in CPU card (though in
most cases the "card" takes up a sizable cor-
ner of the motherboard instead of a vertical
slot. Some examples are ALR (I think) and
IBM's models 90 and 95.
So you unplug the 486SX card and plug in a
486DX card. Problem is these upgrades often
cost more than the $700 or so that a 487SX
costs... the difference is that the clone
makers get the money instead of Intel. And
when the motherboard manufacturer goes under
a couple years later.. 9-)
--
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Iskandar Taib | The only thing worse than Peach ala
Internet: NT...@AQUA.UCS.INDIANA.EDU | Frog is Frog ala Peach
Bitnet: NTAIB@IUBACS !
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Actually (This info comes from an Intel employee), the 486SX was derived from
market pressure from system manufacturers. Not entirely a unilateral decision
on Intel's part to make the chip.
Russ Poffenberger DOMAIN: pof...@sj.ate.slb.com
Schlumberger Technologies UUCP: {uunet,decwrl,amdahl}!sjsca4!poffen
1601 Technology Drive CIS: 72401,276
San Jose, Ca. 95110 (408)437-5254