[Info-vax] RealWorldTech on Poulson

[Michael Kraemer]

Johnny Billquist schrieb:

> 
> True, if you talk about RISC in general, 

that was the competition back then,
forget about x86.

> 
> So, the HP 755 (which shows the better numbers) gives about 80/150 for 
> int and fp, while the Alphas best is 130/200. That's more than what I'd 
> call "marginally better".

For a CPU which was three years late and
which already got a lot of hype before it was available,
a 30% bottom line advantage needing twice the clock rate
is not very impressive.
Moreover, I'm pretty sure the best alpha machine
(a 7000, not a 3000) was way more expensive than the 755.
So even price/performance-wise they weren't the best buy.

> But the big problems with the SpecINT and 
> SpecFP tests that they are so dependant on compilers that they don't 
> really show CPU speeds that you can compare, but show how good your 
> compiler is at compiling for those tests. And yes, compilers many times 
> had (do they still?) code that specifically detected these tests, and 
> popped out specially tuned code for them. So it's questionable how 
> relevant information from such tests are.

It's way more relevant than clock speeds, because they test
the whole system: CPU, RAM, OS, compiler, apps, i.e. exactly
what I buy as a customer. The Spec suite is a well defined
average of different codes, so it wouldn't be easy to cheat
with all of them. Moreover, when the vendors submit results,
they have to specify
exactly the configuration / compiler options they have used.
If some vendor cheats, you bet the competition will notice.
Of course all vendors will tweak their products,
but since they will do in the same direction,
the relative ranking will still be significant.

> 
> I remember walking around various fairs at the time the Alpha was new, 
> and all competitors machines were pretty slow in comparison at the time. 
> It was fun to watch all the vendors trying to show off, and it was 
> painfully obvious that compared to the Alpha they were slow.

I don't know what you saw there, but definitely not real Spec numbers.

> 
> You're right. The R4000 was introduced in 1991, while the Alpha only 
> came in 1992. Got me. :-)
> But I wasn't just talking about addressing, even though that too is 
> nice. But also, all computations and other stuff that requires more than 
> 32 bits will also make a big difference.

I doubt that. 64bit FP was already standard (via IEEE),
and there was only little use for 64bit integers,
except maybe VMS timestamps :-)


> DEC was the second largest computer company in the world only a few 
> years earlier than the Alpha. To call it a "small" company is kindof 
> misstating facts. 

*Relatively* small. It was second to IBM in formal ranking,
but if one looks at real numbers, IBM was a $50B+ company around 1990
and DEC was at $10B+x, iirc. So about a factor of 4 or 5 between them.

> It was probably still, by the time the Alpha was 
> introduced, larger than SUN. However, DEC was definitely not going in 
> the right direction. Mismanagement at many different places.