From owner-freebsd-questions@FreeBSD.ORG Thu May 4 18:06:54 2006 Return-Path: X-Original-To: freebsd-questions@freebsd.org Delivered-To: freebsd-questions@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 1B79E16A415 for ; Thu, 4 May 2006 18:06:54 +0000 (UTC) (envelope-from cswiger@mac.com) Received: from pi.codefab.com (pi.codefab.com [199.103.21.227]) by mx1.FreeBSD.org (Postfix) with ESMTP id B041143D6B for ; Thu, 4 May 2006 18:06:47 +0000 (GMT) (envelope-from cswiger@mac.com) Received: from localhost (localhost [127.0.0.1]) by pi.codefab.com (Postfix) with ESMTP id 1BCE25DAC; Thu, 4 May 2006 14:06:47 -0400 (EDT) X-Virus-Scanned: amavisd-new at codefab.com Received: from pi.codefab.com ([127.0.0.1]) by localhost (pi.codefab.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id ZDcssHTORCwf; Thu, 4 May 2006 14:06:46 -0400 (EDT) Received: from [199.103.21.238] (pan.codefab.com [199.103.21.238]) (using TLSv1 with cipher RC4-SHA (128/128 bits)) (No client certificate requested) by pi.codefab.com (Postfix) with ESMTP id 255DB5C95; Thu, 4 May 2006 14:06:46 -0400 (EDT) In-Reply-To: <9c8168780605041025u234c4cd2s4191a6eacb0de9ad@mail.gmail.com> References: <9c8168780605040928j3c57ec2dne835d4f449abbfab@mail.gmail.com> <9c8168780605041025u234c4cd2s4191a6eacb0de9ad@mail.gmail.com> Mime-Version: 1.0 (Apple Message framework v749.3) Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed Message-Id: Content-Transfer-Encoding: 7bit From: Charles Swiger Date: Thu, 4 May 2006 14:06:44 -0400 To: Kep Woof X-Mailer: Apple Mail (2.749.3) Cc: FreeBSD Questions Subject: Re: which graphics card? X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 04 May 2006 18:06:54 -0000 On May 4, 2006, at 1:25 PM, Kep Woof wrote: >> Sure. For the most part, if you don't have more than 4GB of RAM, >> there is little point to running in 64-bit mode. A more fine-grained >> analysis: > > I think I get it now.. having seen loads of adverts and hype > (particularly from apple) bigging up 64bit, I think i misunderstood > (or never bothered to try to understand more likely). I thought it > meant the bus (or something like that - i obviously know very little > about hardware) was twice as wide and so twice as much data could go > through at once, so it was similar to being twice as fast, or > something like that(!). This impression is partially true, but the subject is complicated. The AMD64 or Intel EM64T platforms do have a better bus, in the case of AMD, HyperTransport is a fairly new and fast backplane which is 16- bits wide at a nominal 1000MHz bus speed, not 64-bits wide or anything like that. The older 32-bit AMD or Intel platforms tended to have a 400-to-533 MHz FSB & memory bus (Intel's "quad-port architecture", VIA's quad-pumped V-link, etc), and the newer 64-bit Intels are 800MHz FSB mostly w/ 533MHz DDR2 memory bus. > Are you saying that it just means you can address more memory? No, the CPU registers and the address bus can be wider (not just the memory bus) with Intel EM64T or AMD64 architectures, and can get more work done per clock for some tasks, but can also be slower for some common tasks, too. Again, if you have more than 4GB of RAM, using the CPU in native 64- bit mode is probably the way to go; if you've got less, using the CPU in 32-bit mode might very well work better, but it really depends upon the type of processes you run. -- -Chuck