From owner-freebsd-hardware@FreeBSD.ORG Mon Jun 18 22:10:23 2007 Return-Path: X-Original-To: freebsd-hardware@freebsd.org Delivered-To: freebsd-hardware@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id 0BEC516A469; Mon, 18 Jun 2007 22:10:23 +0000 (UTC) (envelope-from jdc@parodius.com) Received: from mx01.sc1.parodius.com (mx01.sc1.parodius.com [72.20.106.3]) by mx1.freebsd.org (Postfix) with ESMTP id EE7A613C458; Mon, 18 Jun 2007 22:10:22 +0000 (UTC) (envelope-from jdc@parodius.com) Received: by mx01.sc1.parodius.com (Postfix, from userid 1000) id D60CD1CC044; Mon, 18 Jun 2007 15:10:22 -0700 (PDT) Date: Mon, 18 Jun 2007 15:10:22 -0700 From: Jeremy Chadwick To: Martin Turgeon Message-ID: <20070618221022.GA17952@eos.sc1.parodius.com> References: <4676BAF0.4030703@gmail.com> <20070618180813.GA13003@eos.sc1.parodius.com> <322073cc0706181415o17ecd532i971d8bdf5ea1dafd@mail.gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <322073cc0706181415o17ecd532i971d8bdf5ea1dafd@mail.gmail.com> User-Agent: Mutt/1.5.15 (2007-04-06) Cc: freebsd-hackers@freebsd.org, freebsd-hardware@freebsd.org Subject: Re: i386 with PAE or AMD64 on PowerEdge with 4G RAM X-BeenThere: freebsd-hardware@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: General discussion of FreeBSD hardware List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 18 Jun 2007 22:10:23 -0000 On Mon, Jun 18, 2007 at 05:15:30PM -0400, Martin Turgeon wrote: > My setup is fairly standard (as I described), should I expect problem with > 64 bit version of these programs? Like I said, I don't run 64-bit OSes because I prefer compatibility. Believe me, the instant you run into some quirky problem with either the kernel or any of its subsystems, or a third-party program (from ports or otherwise), the first thing you'll be told is "it works for me on i386, have you tried i386?" I'm sorry if this sounds condescending or combative, but it's what I continually see on other lists. > You'll lose the amount of RAM you're seeing due to PAE addressing for > > PCI address space. I can dig you up a usage map (broken down by how > > much is taken up by each portion; PCI, ACPI, etc.) if you want one. > > It's for SuperMicro systems, but the general idea applies to most > > everything. > > I'm not sure to understand what you mean by that. Are you saying that PAE > will eat the 500M that should be available? PCI addressing is actually responsible for most of it, but it's worse when PAE is in use. This is one of the many reasons a lot of people prefer to run in 64-bit environments. Taken from a Supermicro motherboard manual, documenting the issue (seems their math may be off by 2MB ;) ): http://www.supermicro.com/manuals/motherboard/3000/MNL-0889.pdf 4. Due to memory allocation to system devices, memory remaining available for operational use will be reduced when 4 GB of RAM is used. The reduction in memory availability is disproportional. (Refer to the following Memory Availability Table for details.) System Device Size Physical Memory Remaining (-Available) (4GB Total System Memory) =================================================================== Firmware Hub flash memory 1MB 3.99GB (System BIOS) Local APIC 4KB 3.99GB Area Reserved for chipset 2MB 3.99GB I/O APIC (4 Kbytes) 4KB 3.99GB PCI Enumeration Area 1 256MB 3.76GB PCI Express (256 MB) 256MB 3.51GB PCI Enumeration Area 2 512MB 3.01GB (if needed) -Aligned on 256-MB boundary- VGA Memory 16MB 2.85GB TSEG 1MB 2.84GB ------------------------------------------------------------------- Memory available to OS and 2.84GB other applications =================================================================== -- | Jeremy Chadwick jdc at parodius.com | | Parodius Networking http://www.parodius.com/ | | UNIX Systems Administrator Mountain View, CA, USA | | Making life hard for others since 1977. PGP: 4BD6C0CB |