What do you guys thing about the P4

Phillip D. Matz matz at wsunix.wsu.edu
Sat Apr 14 14:03:47 PDT 2001

Since most people building Beowulfs are doing so to achieve some set of
performance goals - what does the cpu throttling do to a P4-equipped
cluster's performance?

Here is the quote from inquest article to which I'm referring:

"Update:  Intel's Thermal Design Guide has revealed that the absolute
maximum power dissipation of the 1.5GHz P4 is actually 72.9 watts.  This is
33% higher than the published system design specification, and essentially
identical to the 1.33 GHz Athlon.   In order to prevent the CPU from
exceeding 54.7 watt, thermal throttling is used.  If performance critical
applications drive CPU power above its artificially low 54.7 watt limit, the
CPU is halted with a 50% duty cycle (alternating 2 microseconds on; 2
microseconds off) until it cools down. This effectively turns your 1.5GHz
processor into a 750MHz processor - just at the moment you demand peak
performance.   On the other hand, you will probably still be able to check
your email at 1.5GHz.   This scheme is described on page 23 of Intel's P4
Thermal Design Guide.  Commentary is already floating around the web that
perhaps Intel feels guilty about selling 750MHz CPUs in 1.5GHz clothing, and
thus has decided to cut the price by 50% as well."

It sounds like if I build a P4 beowulf for running G98 (or any other
cpu-bound program) that the P4 will be throttled for a good portion of every
day!  Is this true?  comments?

Phillip Matz

----- Original Message -----
From: "Eddie Lehman" <elehman at sunflower.com>
To: <beowulf at beowulf.org>
Sent: Saturday, April 14, 2001 3:20 AM
Subject: Re: What do you guys thing about the P4

> Here is an page pulled from a slasdot.org story in case anyone missed it:
> http://www.inqst.com/articles/p4bandwidth/p4bandwidthmain.htm
> Here is the original slashdot.org story:
> http://slashdot.org/articles/01/04/13/2041238.shtml
> It is to late at night for me to have any thoughts on it right now. Just
> thought it was rather interesting.
> Eddie Lehman
> _______________________________________________
> Beowulf mailing list, Beowulf at beowulf.org
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