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Date:      Wed, 24 Apr 1996 09:42:01 +0300 (EET DST)
From:      "Bror 'Count' Heinola" <count@key.hole.fi>
To:        davidg@Root.COM
Cc:        current@freebsd.org
Subject:   Re: MotherBoard Jumper Settings...
Message-ID:  <199604240642.JAA02764@key.hole.fi>
In-Reply-To: <199604240450.VAA03207@Root.COM> from "David Greenman" at Apr 23, 96 09:50:47 pm

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David Greenman taisi sanoa:
> >	Third, the Oscillator Frequency was set for 33Mhz instead
> >of 25Mhz...have fixed it...
> 
>    Ugh! ...so your 486/100 was running at 133Mhz. Nah, that couldn't
> *possibly* have any bad effects. :-)
> 
> -DG

	AFAIK, DX/4-100 CPU's run only at 3x33MHz _or_ 2x50MHz mode
	which should be jumper selectable on the motherboard. At least
	all motherboards (and CPU's, two AMD's and one Intel) have 
	worked like that. 

	So if external clock is changed to 25MHz, it's effectively 
	working with 75MHz internal clock instead of ~100MHz it's
	supposed to.

	(I used to have a AMD Am5x86-P75-S 133MHz part overclocked to
	160MHz (ie. 4x33MHz -> 4x40MHz) which I used to run FreeBSD on
	but now I've got a P100 for BSD and that machine runs Windows95
	without any problems after I dropped the ISA bus clock down from
	13.33MHz to 10MHz so GUS could keep up.)


-- 
Bror 'Count' Heinola	% count@key.hole.fi	% http://pobox.com/~count/
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Cell: +358-40-5533-554	% Santa Monica Software	% we don't need roads.



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