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Date: Mon, 24 Feb 1997 23:28:08 -0800 (PST)
Message-Id: <199702250728.XAA05308@silvia.HIP.Berkeley.EDU>
To: jin@george.lbl.gov
CC: mark@quickweb.com, freebsd-hardware@freebsd.org,
        kuku@gilberto.physik.rwth-aachen.de, robsch@robkaos.ruhr.de
In-reply-to: <199702250420.UAA09562@portnoy.lbl.gov> (jin@george.lbl.gov)
Subject: Re: Memory speed of P6-200 (256k)
From: asami@vader.cs.berkeley.edu (Satoshi Asami)
Sender: owner-hardware@freebsd.org
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 * > Hmm, how come my new P6NP5 with P6-200 and 96MB RAM (parity mode) can
 * > give me only about:
 * > 
 * > >> dd if=/dev/zero of=/dev/null bs=1m count=1000
 * > 1000+0 records in
 * > 1000+0 records out
 * > 1048576000 bytes transferred in 18.359226 secs (57114390 bytes/sec)

 * Do not waste time to play this game. The "dd" is O.S. dependent code.

Sorry I didn't write the OS version; I am running 3.0 from just before 
the Lite/2 merge.

 * It does not give you what is real memory speed on your system. The result
 * from dd is really depended on the O.S. you are running. If you run 2.2 or
 * higher, you will get much better performance than 2.1.x.

Well I wouldn't ask the list if it's just dd but I've run several
memory tests of my own and this machine always comes out looking very
bad compared to the P5-133 (Triton-II) it replaced.  It's always about 
half, unless the whole thing fits in the 512K L2 cache (in which case
it smokes).

 * 440FX does have worse memory speed than Triton-{I,II}; even though P6 has
 * much better CPU speed, but the PCI controller (440FX) is worse.

I know that.  But there are some people seeing 80MB/s or more and some 
(including myself) who only get about 60MB/s on an apparently
identical chipset.

Satoshi