Date: Thu, 31 Mar 2005 08:45:41 +0930 From: Greg 'groggy' Lehey <grog@FreeBSD.org> To: Scott Long <scottl@samsco.org> Cc: FreeBSD-amd64@freebsd.org Subject: Re: Problems with AMD64 and 8 GB RAM? Message-ID: <20050330231541.GZ84137@wantadilla.lemis.com> In-Reply-To: <424B2FBA.1020102@samsco.org> References: <20050330222439.GU84137@wantadilla.lemis.com> <20050330223546.GA4705@troutmask.apl.washington.edu> <20050330224445.GW84137@wantadilla.lemis.com> <424B2FBA.1020102@samsco.org>
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--vDpQvD79HZx/5O2q Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Wednesday, 30 March 2005 at 16:01:14 -0700, Scott Long wrote: > Greg 'groggy' Lehey wrote: >> On Wednesday, 30 March 2005 at 14:35:46 -0800, Steve Kargl wrote: >> >>> On Thu, Mar 31, 2005 at 07:54:39AM +0930, Greg 'groggy' Lehey wrote: >>> >>>> None of these problems occur when I use 4 GB memory. About the only >>>> strangeness, which seems to come from the BIOS, is that it recognizes >>>> only 3.5 GB. If I put all DIMMS in, it recognizes the full 8 GB >>>> memory. >>> >>> I had 4 bad out of 12 tested where the DIMMs were Crucial PC2700 2GB >>> Reg. ECC DIMMs. >> >> OK, this makes sense. It might also explain why the 4 GB >> configuration only recognizes 3.5 GB. > > No, and I'm going to make this an FAQ and post it in a very obvious > place, since 4+ GB is so easy to get and people don't seem to understand > the PC architecture very well. That's not easy to understand when it's barely documented. Thanks for the info: it helps a lot. This may still be a hint, though: that memory hole doesn't show up during a boot with 8 GB RAM. How come? Is the system trying to map RAM over the PCI hole? It looks as if I should get a verbose boot listing with 8 GB. It'll be a couple of hours before I find time to reboot this machine. In the meantime, there's a verbose boot with 4 GB at http://www.lemis.com/grog/Images/20050331/obelix-dmesg. I'm told it shows a number of strange things, including incorrect reporting of on-chip cache sizes. Greg -- See complete headers for address and phone numbers. --vDpQvD79HZx/5O2q Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.6 (FreeBSD) iD8DBQFCSzMdIubykFB6QiMRAkrBAKCESZB6S1NDAmsQhPl+wU5aHK06wQCfQxOO XSLk29dQDExbNfzD9Nwsxys= =W5rD -----END PGP SIGNATURE----- --vDpQvD79HZx/5O2q--
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