From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from lists.gentoo.org ([140.105.134.102] helo=robin.gentoo.org) by nuthatch.gentoo.org with esmtp (Exim 4.43) id 1EF2lh-0005kD-Ln for garchives@archives.gentoo.org; Tue, 13 Sep 2005 04:51:42 +0000 Received: from robin.gentoo.org (localhost [127.0.0.1]) by robin.gentoo.org (8.13.4/8.13.4) with SMTP id j8D4kKLS029449; Tue, 13 Sep 2005 04:46:20 GMT Received: from wproxy.gmail.com (wproxy.gmail.com [64.233.184.198]) by robin.gentoo.org (8.13.4/8.13.4) with ESMTP id j8D4geO3018911 for ; Tue, 13 Sep 2005 04:42:42 GMT Received: by wproxy.gmail.com with SMTP id i5so2695663wra for ; Mon, 12 Sep 2005 21:47:11 -0700 (PDT) DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:message-id:date:from:reply-to:to:subject:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=adgBDO3z9HZK/hA8cbWMmK2IOR7MgH2bEzBQ1jMH8nBeZrnfzmPfdW02YjqZLJHqNbBJ4qEugh5g9VXw7BYiUhIhrcAqA+MrPO8qi+IBRZnmyjRPvocO/7EG/Wxn11cy5ioQGC47mSEmXoBHH6dh8SSAy5iXhsstdYV+kS/pR6Q= Received: by 10.54.137.13 with SMTP id k13mr221019wrd; Mon, 12 Sep 2005 21:47:11 -0700 (PDT) Received: by 10.54.109.6 with HTTP; Mon, 12 Sep 2005 21:47:11 -0700 (PDT) Message-ID: Date: Mon, 12 Sep 2005 23:47:11 -0500 From: Denis To: gentoo-user@lists.gentoo.org Subject: Re: [gentoo-user] hardware advice for dual-processor set-up on gentoo In-Reply-To: Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-Id: Gentoo Linux mail X-BeenThere: gentoo-user@gentoo.org Reply-to: gentoo-user@lists.gentoo.org Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Disposition: inline References: <20050912200733.3da4cc99@chi.speakeasy.net> Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from quoted-printable to 8bit by robin.gentoo.org id j8D4geO3018911 X-Archives-Salt: 9257ab4e-0845-49a7-8404-690f049e8a19 X-Archives-Hash: c15e97460f6a87b70e23a6a5e387d9bd Ok, I felt compelled to find more info on the issue that Bob raised with the memory bandwidth limitation on the Opterons, and here is an excerpt from an article on anandtech.com on this issue: "The one limitation that both AMD and Intel have is bandwidth. In order to maintain compatibility with present day Socket-940 and Socket-939 motherboards, AMD could not increase the pincount of their dual core processors. The benefit is that AMD's dual core CPUs will work in almost all Socket-940 and Socket-939 motherboards (more on this later), but the downside is that the memory bus remains unchanged at 128-bits wide and supports a maximum memory speed of DDR400. So, while single core Athlon 64 and Opteron CPUs get a full 6.4GB/s of memory bandwidth, today's dual core CPUs are given the same memory bandwidth to share among two cores instead of one. AMD's solution to the problem will come in the form of DDR2 and a new socket down the road, but for now there's no getting around the memory bandwidth limitations. Intel is actually in a better position from a memory bandwidth standpoint. At this point, their chipsets provide more memory bandwidth than what a single core needs with their dual channel DDR2-667 controller. The problem is that the Intel dual core CPUs still run on a 64-bit wide 800MHz FSB, which makes Intel's problem more of a FSB bandwidth limitation than a memory bandwidth limitation." So basically... I would pretty much be buying an already outdated technology if I were to purchase a dual Xeon or a dual Opteron system now? I guess the other advantage is that a good dual Xeon system with 4GB RAM will run me around $3000, whereas a dual Opteron (with dual core) system with 4GB RAM will run me more like $4300. If the Opterons are currently at their memory bandwidth limit, I will have spent the $4300 for nothing, especially since I need the fastest memory integration I can get for my codes. Would I be better buying a dual Xeon system if I needed to buy right now instead of waiting for the bandwidth issue to be resolved? -- gentoo-user@gentoo.org mailing list