From owner-freebsd-hardware Mon Sep 30 23:58:09 1996 Return-Path: owner-hardware Received: (from root@localhost) by freefall.freebsd.org (8.7.5/8.7.3) id XAA01818 for hardware-outgoing; Mon, 30 Sep 1996 23:58:09 -0700 (PDT) Received: from mx.serv.net (mx.serv.net [199.201.191.10]) by freefall.freebsd.org (8.7.5/8.7.3) with ESMTP id XAA01813 for ; Mon, 30 Sep 1996 23:58:07 -0700 (PDT) Received: from MindBender.serv.net by mx.serv.net (8.7.5/SERV Revision: 2.30) id XAA24758; Mon, 30 Sep 1996 23:58:10 -0700 (PDT) Received: from localhost.HeadCandy.com (michaelv@localhost.HeadCandy.com [127.0.0.1]) by MindBender.serv.net (8.7.5/8.7.3) with SMTP id XAA12968; Mon, 30 Sep 1996 23:30:43 -0700 (PDT) Message-Id: <199610010630.XAA12968@MindBender.serv.net> X-Authentication-Warning: MindBender.serv.net: Host michaelv@localhost.HeadCandy.com [127.0.0.1] didn't use HELO protocol To: Narvi cc: "David E. O'Brien" , freebsd-hardware@freebsd.org Subject: Re: H/W recommendation In-reply-to: Your message of Mon, 30 Sep 96 23:26:46 +0300. Date: Mon, 30 Sep 1996 23:29:38 -0700 From: "Michael L. VanLoon -- HeadCandy.com" Sender: owner-hardware@freebsd.org X-Loop: FreeBSD.org Precedence: bulk >> 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... -----------------------------------------------------------------------------