re: AMD (fwd)

Rob Glover (potato@dsnet.com)
Sat, 21 Dec 1996 17:03:38 -0800 (PST)


On Sat, 21 Dec 1996, Jim Nance wrote:

>
> Forwarded message:
>
> > > What is it missing that makes it non-pentium-class?
> > >
> > > Jim
>
> > Well look at what he just said:
> >
> > its a 486 CPU that just has its internal clock quadrupled....
> >
> > here is an example.. a 486dx2-66 is just a 486 33MHz CPU with its internal
> > clock DOUBLED, to make it 66MHz. The same idea as above.. the CPU above
> > is jsut a 486-33 class CPU with its internal clock QUADUPLED. 33 * 4 =
> > 132. <they do a bit of funny math to work it up to 133 :>
>
> OK, let me phrase my question a little better, and give my motiviation for
> asking it. I frequently see statements that AMD and Cyrix 586 processors
> are not "real" pentium CPUs, and there is usually the implication that
> that this is a bad thing. I am trying to figure out how much of the
> difference it really a bad thing, and how much is marketing hype.
> Perhaps I should have asked if a Pentium was more than a fast 386.
>
> Here are my questions, and what I know about the answers, in a little
> more detail:
>
> 1) Are there any instructions available with the Pentium that are not
> available with the AMD chip. How important are they? Does the
> AMD part have useful instructions that the Pentium does not?
>
> The only thing I can think of that might fall into this catagory is
> the 4M page table stuff, but I am not well versed in this subject.
>
> 2) Can the Pentium perform tasks that can not be performed with the AMD
> processor?
>
> I dont think so. I believe that each of them can address the same amount
> of ram, the registers are the same size, etc. The Pentium may be better
> for SMP stuff, but I suspect that you dont even have the choice of using
> and AMD processor if that is the case.
>
> 3) Is the Pentium a better value for the money?
>
> I suspect that the Pentium will run faster at a given clock speed, and
> I suspect that the AMD part is cheaper. I am just guessing though.
>
>
> Thanks,
>
> Jim
>
>
Pentium = All Pentium optizmizations
AMD 5x86 = All 486 Stuff, no Pentium stuff.

A Pentium is a Pentium, a AMD5x86 is a 486, just made run to quadrupled in
speed, no added Pentium instructions or anything.... AMD5x86 can do
everything a 486 can, but can't do everything a Pentium can, because it
dosen't have any Pentium instructions. here are answers to your
questions, in order:

1) No. AMD5x86 only has 486 instructions. Pentium has Pentium
instructions.

2) A AMD5x86 can't do everything a Pentium can, because it doen't have
any Pentium instructions.

3) I would say the Pentium is worth the extra $$$. If you get that 5x86
now, you'll regret it later down the road. If you get the Pentium,
you'll regret it a lot later down the road :>

Hope this clarifies things :>

-Rob