What do you guys thing about the P4

Phillip D. Matz matz at wsunix.wsu.edu
Fri Apr 13 13:24:48 EDT 2001


Hi,

> especially with a compiler that can use the SSE side
> of the microprocessor.

Which brings up another question.  My current impression was that SSE/SSE2
is only single-precision while G98 (and probably most computational
chemistry programs) requires double-precision -> if this is correct then SSE
doesn't help, rather, it invalidates ones G98 results.  Would anyone care to
set me straight?

Thanks,

Phillip Matz
matz at wsunix.wsu.edu

----- Original Message -----
From: "Richard Walsh" <rbw at networkcs.com>
To: <beowulf at beowulf.org>; <lindahl at conservativecomputer.com>
Sent: Friday, April 13, 2001 9:16 AM
Subject: Re: What do you guys thing about the P4


>
> All,
>
> I believe the arithmetic behind the 3.2 Gbyte/sec peak
> memory bandwidth in P4 system using PC800 RDRAM, and
> Intel's 850 (Tehama) chip set is as follows:
>
>       RDRAM memory speed        =   400 MHz
>       RDRAM channel width       =    x2 bytes
>       RDRAM "pumps" per cycle   =    x2
>       RDRAM channels on 850     =    x2
>       ---------------------------------------
>       Total On Board Bandwith   =  3200 MBytes/sec
>
>       P4 system bus speed       =   400 MHz
>       P4 system bus width       =     8 bytes
>       ---------------------------------------
>       Total On Chip Bandwith    =  3200 MBytes/sec
>
> (a single channel SDRAM system is  8*133=1.06 GBytes/sec)
>
> So P4/850 motherboards with PC800 RDRAM are well balanced.
> Problems with large linear systems, and cache and memory
> resonant reference patterns will keep the processor
> relatively busy and hide the RDRAM latency penalty
> which is about 2x that of SDRAM (the P4's faster clock
> also helps to reduce this penalty).
>
> I would expect G98 jobs run INCORE or DIRECTly with a
> large memory setting to show excellent performance
> especially with a compiler that can use the SSE side
> of the microprocessor.
>
> rbw
>
> #---------------------------------------------------
> #
> # Richard Walsh
> # Project Manager, Financial Markets
> # netASPx, Inc.
> # 1200 Washington Ave. So.
> # Minneapolis, MN 55415
> # VOX:    612-337-3467
> # FAX:    612-337-3400
> # EMAIL:  rbw at networkcs.com, richard.walsh at netaspx.com
> #
> #---------------------------------------------------
> # "What you can do, or dream you can, begin it;
> #  Boldness has genius, power, and magic in it."
> #                                  -Goethe
> #---------------------------------------------------
> # "Without mystery, there can be no authority."
> #                                  -Charles DeGaulle
> #---------------------------------------------------
>
>
> _______________________________________________
> Beowulf mailing list, Beowulf at beowulf.org
> To change your subscription (digest mode or unsubscribe) visit
http://www.beowulf.org/mailman/listinfo/beowulf
>


_______________________________________________
Beowulf mailing list, Beowulf at beowulf.org
To change your subscription (digest mode or unsubscribe) visit http://www.beowulf.org/mailman/listinfo/beowulf



More information about the Beowulf mailing list