Problems with AMD64 and 8 GB RAM?

Willem Jan Withagen wjw at
Tue Apr 5 00:33:08 PDT 2005

Greg 'groggy' Lehey wrote:
> I've recently acquired an AMD64 box (dual Opteron 242, SiS Master at -FAR
> motherboard
> (
> See below for more details).  I find it very unstable running with 8
> GB memory, though 4 GB are not a problem.  At first I thought it was
> the onboard peripherals, but after disabling them it still persisted.
> What's unstable?  I only once got it through the boot process.
> Running a 5.3-RELEASE i386 kernel it panics, though I haven't
> investigated the panic (yet), since I'm not interested in the i386
> kernel.  The amd64 5.4-PRERELEASE kernel just hangs/freezes.  When the
> peripherals are enabled, it's after probing the onboard NIC (bge) and
> before probing SATA (no drives present).  I've done a verbose boot, of
> course, but no additional information is present.  The NIC is
> recognized, and that's all.
> Without the peripherals, but with a 3Com 3c905 PCI NIC, it continues
> beyond this point, but doesn't enable the NIC.  I don't have dmesg
> output for these attempts, so I can't produce the exact message, and I
> suspect it's not important.  It continues until trying to mount NFS
> file systems, where it hangs for obvious reasons.  Pressing ^C causes
> the system to either panic (and be unable to dump because I don't have
> that much swap) or just hang.
> 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 realize that this isn't enough to diagnose the problem.  The reason
> for this message now is to ask:
> 1.  Has anybody else seen this problem?

Hi Greg,

[Currently little time so I'll dig the archives later for more details]

I'm sorry to come into this discussion after 58 messages, but this board has 
been extensively discussed about 1 year ago, because it gave me trouble to no 
end (even with 2Gb). One of the early amd64 developers (not David or Scott) 
had the same board but could not get it stable under amd64 (i386 was fine with 
2Gb). He tossed it, and suggested me to do the same. Which I did, and went to 
a Tyan board S278. After that there where no more problems at all. At the time 
I think things we're at 5.1 so now with 5.3 some features might have made the 
board act more stable.


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