Xref: utzoo comp.lang.fortran:910 comp.unix.questions:8211
Path: utzoo!attcan!uunet!yale!cmcl2!phri!roy
From: roy@phri.UUCP (Roy Smith)
Newsgroups: comp.lang.fortran,comp.unix.questions
Subject: Re: Sun 3 vs uVAXII floating point speed....
Message-ID: <3381@phri.UUCP>
Date: 14 Jul 88 12:45:10 GMT
References: <25065@ucbvax.BERKELEY.EDU>
Reply-To: roy@phri.UUCP (Roy Smith)
Distribution: na
Organization: Public Health Research Inst. (NY, NY)
Lines: 29

ao@cevax.berkeley.edu (Akin Ozselcuk) writes:
> I am posting this article on behalf of a friend of mine who is planning
> to buy either a Sun3 or a VAX Station 2000 (a watered down uVAXII).  He
> is planning to do a lot of number crunching by using f77.

	Asking if a uVAX or a Sun-3 is faster for floating point is a
misleading question, or at least an imcomplete one.  Are you talking about
a 3/50 without even the 68881 option or a 3/260 with FPA?  The difference
in floating point speed between the two is at least an order of magnitude.

	By way of comparison, we have an 11/750 with FPA, 3/50s both with
and without 68881s and 3/160s with FPAs.  To give you some feel for the
rough relative speeds (notice the use of lots of ambigiuating terms; you're
mileage will vary depending on zillions of factors), we find that a 3/50
with 68881 and the 750 with FPA are roughly the same speed.  A 3/160 with
FPA is about 10 times faster than that.  From what I understand, the 3/260
(which we don't have) uses exactly the same FPA board as the 160 so for
floating-point intensive applications, the 260 is not a whole lot faster
than the 160.  My guess is that the uVAX-II is about the same speed as a
750.

	Another factor to consider is that Sun's new snazzy Fortran
compiler is supposed to produce *much* faster code than the generic Unix
f77 compiler.
-- 
Roy Smith, System Administrator
Public Health Research Institute
{allegra,philabs,cmcl2,rutgers}!phri!roy -or- phri!roy@uunet.uu.net
"The connector is the network"