[plug] Re: Cyrix speeds

[Bret Busby]

Matt Kemner wrote:
> 
> On Sun, 6 Aug 2000, Kai wrote:
> 
> > I used to have a Cyrix processor and for some reason the speed they identify
> > at is not their true speed !
> > I compared my Cyrix 6x86 (200 MHz) against a mates 200 MHz intel and the
> > Cyrix was outperformed.

What was the comparison? How was it done? That is the critical thing, in
benchmarking. See quote at the end of message below.

> 
> That is because when Cyrix named their processors they chose to
> "benchmark" the cyrix against the pentiums, using a benchmark where the
> cyrix excelled at, and rated the Cyrix according to that - the "PR" in
> "Cyrix PR-200" means Pentium Rating 200 - so they consider it equivalent
> to a Pentium 200, even though it is probably only 133MHz or so, and gets
> outperformed even by a Pentium of equivalent MHz in most real-world
> applications.
> 
> It's what happens when you let Marketing guys loose.
> 
>  - Matt

>From what I understand, there are some different issues here.

One thing; I understood that where Cyrix used the "PR", it was supposed
to relate to the Pentium Pro chip, as opposed to the standard Pentium
chip. The format of the name of a standard Pentium equivalent chip, was
as in the next paragraph.

We have two Cyrix 6x86 boxes. My computer is based on a a Cyrix 6x86
P150+, which is supposed to be the equivalent of at least an Intel
Pentium, running at 150MHz. The clockspeed for the CPU, is 120MHz. The
other computer has a Cyrix P120+, running at a clockspeed of 100MHz, and
is supposed to be the equivalent of at least an Intel Pentium 120MHz.
>From memory, the inclusion of the "PR" in the chip name, was after the
Pentium equivalent clockspeed, eg, Cyrix 6x86 P200PR, or, something like
that. But, these chips are fairly old; it was a long time ago, and, my
memory may be wrong in that (old RAM tends to wear out...).

However, from what I understand, the Cyrix 6x86's, have only the
instruction set of an Intel 486.

I have previously run various benchmarking tests, that give various
relative speeds for the CPU in my computer, but from memory, it seems to
be about the equivalent of an Intel Pentium, running at 75-90MHz.

Regarding the being "outperformed by a Pentium of equivalent MHz in most
real world applications", from memory, the Cyrix Pentium equivalent (or,
regarded as equivalent, anyway) CPU's, are supposed to be faster than
the Intel Pentium chips of the equivalent-rated clock-speed, for
database applications, but, slower for fpu operations, such as
calculation intensive work, like graphics, mathematical applications,
etc.

The Intel chips, from memory, are supposed to be the best of the CISC
chips for games, but it all goes to the question of the purpose of the
computer. I haven't played a game on my computer, since my last system
rebuild about a year and a half ago, as I still haven't got around to
reinstalling National Lampoon's Chess Maniac 5 Billion and One, which is
a 16-bit Windows application. I still don't have enough room. And, my
computer was plenty good enough for that game. I still haven't been able
to get the sound on my computer working again, but I don't regard that
as too important (apart from doing things like playing games, which
haven't been very important to me).

In terms of BogoMIPS, a while ago, I did a comparison of the BogoMIPS
ratings of a 486DX running RH 6.0, my computer with the Cyrix 6x86
P150+, an AMD K62-300 running RH 6.0, and compared them with Bill
Kenworthy's system, running a Mandrake version (7.0, I believe, from
memory), and, the results appeared to be reasonable and comparative,
approximately, if not exactly, linearly related to the relative CPU
capacities. So, between these differing versions of Linux, with
differing kernels, the results appeared consistent.

-- 

Bret Busby

"I think the problem, to be quite honest with you, is that you've never
actually known what the question is."... "So once you do know what the
question actually is, you'll know what the answer means." - Deep
Thought, Chapter 28 of The Hichhiker's Guide to the Galaxy- Douglas
Adams, 1988 

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