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Date:      02 Feb 1998 18:13:47 +0100
From:      dag-erli@ifi.uio.no (Dag-Erling Coidan Smørgrav)
To:        hackers@FreeBSD.ORG
Subject:   Re: Overclocking a Pentium 120
Message-ID:  <xzpoh0q6ib8.fsf@hrotti.ifi.uio.no>
In-Reply-To: "Ross Potts"'s message of "Mon, 2 Feb 1998 09:32:18 -0500"
References:  <9802020845.ZM7015@unknown.zmail.host>  	<xzpzpkaaymw.fsf@grjottunagard.ifi.uio.no> <9802020932.ZM7015@unknown.zmail.host>

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"Ross Potts" <rpotts@med.osd.mil> writes:
> ACtually , I could just swap a 133 from work, clock it to 150, then put my 120 
> in at work and clock it to 133.  I'm such a dirty bum!

IMHO, if you ask for advice, you should at least be prepared to listen
to what you actually get.

A 150 Mhz Pentium is clocked at 60 MHz externally, while a 133 Mhz
Pentium is clocked at 66 Mhz. This means that RAM, L2 cache, the
motherboard chipset (including I/O controllers) and the PCI bus (which
runs at half the bus clock, i.e. 30 or 33 MHz) is slower in a 150 MHz
machine than in a 133 MHz machine. Be my guest and count on your
fingers: that's practically the entire computer! The only situation in
which a 150 MHz machine beats a 133 MHz machine is when doing a very
long series of very simple calculations on very small data sets (i.e.
data sets which fit entirely into the L1 cache - *not* the L2 cache
since it is clocked at bus speed). That situation is practically never
encountered in real applications, and most certainly not while running
a task-switching OS such as FreeBSD.

You will gain *nothing* by overclocking your 120 or 133 MHz Pentium to
150 MHz.

If you still don't believe me, check out the URL I gave you earlier
today. You will find benchmark results of various processors run at
various bus speeds and clock multiplier settings.

And, the 133 MHz processor you have at work will probably not run any
better at 150 MHz than the 120 MHz you have at home, because the odds
are that the 120 MHz is a 133 Mhz chip, re-marked by Intel to fill the
demand for 120 MHz chips.

Finally, I don't know if I like your attitude very much. Overclocking
is a nice feature, not a God-given right. If your processor runs well
when overclocked, fine. If it doesn't, don't complain - you got what
you paid for in the first place, no more, no less.

-- 
 * Finrod (INTJ) * Unix weenie * dag-erli@ifi.uio.no * cellular +47-92835919 *
  RFC1123: "Be liberal in what you accept, and conservative in what you send"



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