From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Wed, 20 Jun 2001 15:42:42 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Wed, 20 Jun 2001 15:42:32 -0400 Received: from sal.qcc.sk.ca ([198.169.27.3]:28942 "HELO sal.qcc.sk.ca") by vger.kernel.org with SMTP id ; Wed, 20 Jun 2001 15:42:24 -0400 Date: Wed, 20 Jun 2001 13:42:21 -0600 From: Charles Cazabon To: linux-kernel@vger.kernel.org Subject: Re: Threads FAQ entry incomplete Message-ID: <20010620134221.C12357@qcc.sk.ca> In-Reply-To: <20010620104800.D1174@w-mikek2.des.beaverton.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2i In-Reply-To: ; from yoda@isr.ist.utl.pt on Wed, Jun 20, 2001 at 07:59:29PM +0100 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Rodrigo Ventura wrote: > > BTW, I have a question: Can the availability of dual-CPU boards for intel > and amd processors, rather then tri- or quadra-CPU boards, be explained with > the fact that the performance degrades significantly for three or more CPUs? > Or is there a technological and/or comercial reason behind? Commercial reasons. Cost per motherboard/chipset goes way up as the number of CPUs supported goes up. For each CPU that a chipset supports, it has to add a lot of pins/lands, and chipsets are already typically land-limited. Motherboard trace complexity (and therefore number of layers) goes up. Add to that that the potential market goes down as CPUs goes up. You can buy 4-, 8-, and 16-way motherboards for Intel CPUs (don't know about more). But the 16-way ones will cost as much as a house. Charles -- ----------------------------------------------------------------------- Charles Cazabon GPL'ed software available at: http://www.qcc.sk.ca/~charlesc/software/ Any opinions expressed are just that -- my opinions. -----------------------------------------------------------------------