Date: Mon, 30 Sep 1996 23:29:38 -0700 From: "Michael L. VanLoon -- HeadCandy.com" <michaelv@MindBender.serv.net> To: Narvi <narvi@haldjas.folklore.ee> Cc: "David E. O'Brien" <obrien@nuxi.cs.ucdavis.edu>, freebsd-hardware@freebsd.org Subject: Re: H/W recommendation Message-ID: <199610010630.XAA12968@MindBender.serv.net> In-Reply-To: Your message of Mon, 30 Sep 96 23:26:46 %2B0300. <Pine.BSF.3.91.960930232410.7487C-100000@haldjas.folklore.ee>
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>> It's pretty simple for real Pentiums (or 486s). Anything that is an
>> even multiple of 33 1/3 (read things as 133.3... 166.667...) runs the
>> memory bus at 66 2/3 MHz (i. e. "166"MHz Pentium is 2.5 * 66.67MHz).
>> Anything that isn't an even multiple of of 33.3, and is an even
>> multiple of 30, runs the PCI bus at 60MHz. The only other option
>> that's left is multiples of 25 (75MHz Pentiums).
>Grrrr..... Pentiums being "even multiplies of 30" (60, 120, 150) run the
>memory bus at 60 Mhz and the PCI bus at 30 Mhz.
Argh. That's what I meant. Unfortunately, that's not what my fingers
typed.
>The Pentium 75 runs the
>memory bus at 50 Mhz and the PCI bus at 25 Mhz. 75 == 1.5*50
That's what I implied (following the logic outlined above), but
apparently didn't make explicitly clear. Multiples of 25: the memory
bus runs at 50MHz, and the PCI bus runs at 25MHz.
>> The PCI bus on a Pentium runs at half the memory bus speed (the speed
>> from the CPU to memory and cache). 486s run the memory bus at the
>> same speed as the PCI bus (i. e. 30 or 33.3MHz in most cases).
[...]
To clarify:
Even Memory PCI bus
Multiple bus speed speed
MHz MHz MHz
-------- --------- -------
33.3 66.67 33.3
30.0 60.00 30.0
25.0 50.00 25.0
-----------------------------------------------------------------------------
Michael L. VanLoon michaelv@MindBender.serv.net
--< Free your mind and your machine -- NetBSD free un*x >--
NetBSD working ports: 386+PC, Mac 68k, Amiga, Atari 68k, HP300, Sun3,
Sun4/4c/4m, DEC MIPS, DEC Alpha, PC532, VAX, MVME68k, arm32...
NetBSD ports in progress: PICA, others...
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