From owner-freebsd-questions@FreeBSD.ORG Thu May 4 16:42:56 2006 Return-Path: X-Original-To: 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 7E24F16A41B for ; Thu, 4 May 2006 16:42:56 +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 B54A943D45 for ; Thu, 4 May 2006 16:42:49 +0000 (GMT) (envelope-from cswiger@mac.com) Received: from localhost (localhost [127.0.0.1]) by pi.codefab.com (Postfix) with ESMTP id 05AFA5DAC; Thu, 4 May 2006 12:42:49 -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 NUvRD-2jm2tm; Thu, 4 May 2006 12:42:48 -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 1F1715C98; Thu, 4 May 2006 12:42:48 -0400 (EDT) In-Reply-To: <9c8168780605040928j3c57ec2dne835d4f449abbfab@mail.gmail.com> References: <9c8168780605040928j3c57ec2dne835d4f449abbfab@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 12:42:47 -0400 To: Kep Woof X-Mailer: Apple Mail (2.749.3) Cc: questions@freebsd.org 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 16:42:56 -0000 On May 4, 2006, at 12:28 PM, Kep Woof wrote: > it seems like a huge waste to run the i386 version on an > amd64 machine, but can anyone comment on the performance difference? 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: You can still take advantage of PAE and more than 4GB process address space on, say, a machine with 2GB of RAM, by using a lot of swap space or running a large 64-bit aware database. However, if you don't have more than 4GB of RAM [1], it's entirely possible that applications will run faster in 32-bit mode than in 64-bit mode, but it depends on the specific things you are running. IPv4 and character-related stuff (ie, byte fiddling/string copying) tend to be faster in 32-bit mode; things like SSL cryptography and big databases can prefer 64-bit mode even on machines without more than 4GB of RAM. -- -Chuck [1]: The real number is actually somewhat less than 4GB, more like 3GB or 3.5GB, since the kernel itself and hardware devices consume some of the top of the physical memory address map.