am2 MBs - 4g + SCSI wipes out root partition

Gary Jennejohn gary.jennejohn at
Mon Oct 13 13:21:31 UTC 2008

On Mon, 13 Oct 2008 13:55:22 +0100
Pete French <petefrench at> wrote:

> > David, Fabian, and Adam -- are any of you using your cards in an
> > AM2-based system?
> This suddenly has ccaught my attention - I have one AM2 system, and
> it will not boot amd64, and will only boot i386 in safe mode. In both
> cases the problems appear to be when it probes my SCSI RAID card.
> Having said that, I had a different motherboard with the same parts on it
> which ran BSD fine. but this one appears not to, and is AM2.

I have seen weird problems with two AM2 motherboards and 4GB of memory.

In one case, using an Adaptec 29160 (ahc) and amd64 (64 bit) I saw data
corruption.  Note that the same setup worked just fine with i386 because
FreeBSD ignored the memory mapped above 4GB.

The other board failed to map any memory above 4GB when a PCI card was
plugged in and FreeBSD saw only about 3GB.  Might be a bug in the BIOS
or an option which I failed to set - I didn't spend much time on it.

Gary Jennejohn

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