Tyan k8sr lockups

[Vivek Khera]

I have a brand new Tyan k8sr based system with a megaraid 320-2X  
controller in it.

This is my second copy of this box (the first one is being replaced  
since it keeps locking up and reporting "memory size changed" in the  
BIOS, even with a new motherboard)...

Anynow, this particular machine has just simply locked up with no  
errors reported to console or syslog or BIOS.  It does have a newer  
BIOS rev, so perhaps that is why nothing is logged to BIOS...  This  
happens during times of heavy loads (large database reports, database  
dump, database replication all simultaneously running).  If the machine  
doesn't crash, I'll see a "bge0 timeout -- resetting" in the syslog  
most days during the time of heavy load (reports run on a remote  
client).

I see at  
http://unix.derkeiler.com/Mailing-Lists/FreeBSD/hackers/2005-03/ 
0419.html that this is happening to at least one other person on this  
motherboard, but using the on-board controller.

Someone else just noted similar lockups with 5.3 with SMP running  
mysql, and about 2 weeks ago there was a discussion about amr driver  
panic under 5.4-PRERELEASE, both on the stable@ list.  However these  
were not amd64 systems, if that matters.

FreeBSD 5.4-PRERELEASE as of March 22, 2005 is running on this system.   
It has a dual Opteron 246 2GHz and 4GB RAM.

Could it be some strange interaction of the K8SR and the 320-2X  
megaraid card?  This makes two machines exhibiting very unstable  
behavior, and I've already replaced the motherboard on one of them.