Date: Tue, 5 Apr 2005 10:09:11 +0930 From: Greg 'groggy' Lehey <grog@FreeBSD.org> To: freebsd-stable@FreeBSD.org, FreeBSD-amd64@FreeBSD.org Subject: Re: Problems with AMD64 and 8 GB RAM? (solved) Message-ID: <20050405003911.GT867@wantadilla.lemis.com> In-Reply-To: <20050331184524.GB1687@dragon.NUXI.org> <20050331185902.GF1687@dragon.NUXI.org> References: <424B308C.7070506@samsco.org> <20050330230951.GY84137@wantadilla.lemis.com> <200503301525.37798.peter@wemm.org> <20050331184524.GB1687@dragon.NUXI.org> <20050330222439.GU84137@wantadilla.lemis.com> <20050330223546.GA4705@troutmask.apl.washington.edu> <20050330224445.GW84137@wantadilla.lemis.com> <200503311032.33718.doconnor@gsoft.com.au> <20050331015429.GH6252@wantadilla.lemis.com> <20050331185902.GF1687@dragon.NUXI.org>
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--owPIoVL9FiqC4k42 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Thursday, 31 March 2005 at 10:59:02 -0800, David O'Brien wrote: > On Thu, Mar 31, 2005 at 11:24:29AM +0930, Greg 'groggy' Lehey wrote: >> On Thursday, 31 March 2005 at 10:32:33 +0930, Daniel O'Connor wrote: >>> On Thu, 31 Mar 2005 08:14, Greg 'groggy' Lehey wrote: >>>>> Have you run sysutils/memtest86 with the 8 GB? >>>> >>>> Heh. Difficult when the system doesn't run. >>> >>> You could try http://www.memtest86.com although that doesn't do >4Gb >> :( >> >> I'm pretty sure it's not the memory. I've tried each pair >> individually, and it's only when they're both in there together that >> it's a problem. And yes, I've tried them in each pair of slots. > > You have a dual-channel memory controller. If you insert one DIMM you > perform 64-bit data accesses. If you install DIMM's in pairs (making > sure you're using the right "paired" sockets), you perform 128-bit data > accesses. Thus your access pattern is different between these two > situations. I'm highly suspious that you can us 4x2GB DIMM's with out > knowing the exact part number. Don't forget 2GB DIMM's are > double-stacked and thus look like double the electrical bus loads. The > same is true for older 1GB DIMM's. This looks like it's the issue. > Install all the memory you would like to use into your motherboard, > download memtest86+ version 1.40 from http://www.memtest.org, dd to > floppy or burn the ISO, and report back your findings from running > it. Done that. It was quite revealing. This particular motherboard and BIOS supply either "ECC off" or "ECC in chip kill mode". Mine was off, and I got many errors. With 4 GB (any two chips) and chip kill mode enabled, I ran memtest86+ for about 18 hours and got about 1 ECC error per second. With 8 GB, with or without chip kill, neither FreeBSD, memtest86+ nor Linux run reliably: memtest86+ spontaneously reboots every 5 minutes or so. I borrowed this memory to test the motherboard, and it's going back this week anyway. I now have my own memory :-(all 1 GB of it), and it tests perfectly. The memory I had the trouble with works perfectly in the machine for which it was purchased, so it does indeed look like an electrical loading problem. The moral of the story is, I suppose, "don't buy the MSI K8T Master2-FAR". I was warned about the motherboard before I bought it, but at the time it was the only game in town. Now I know of other places with (hopefully) better boards. Greg -- See complete headers for address and phone numbers. --owPIoVL9FiqC4k42 Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.6 (FreeBSD) iD8DBQFCUd4vIubykFB6QiMRAnGRAKCXlMCMuXYu8rl5aTPjbIEoV5sXsgCgjNGK 5HSPyah1wMt/D4gNJFSv/0E= =QwJ8 -----END PGP SIGNATURE----- --owPIoVL9FiqC4k42--
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