How to debug >2GB memory issues (and 3ware)

[Michael R. Wayne]

I have a Dual 4GB system with a 3ware SATA controller that's working
properly as long as I restrict it to 2GB with:
   hw.physmem=2G

Obviously, I'd like to have access to the other 2GB of RAM.  But
if I go past 2GB, I get random crashes during all builds (world,
kernel, port).

Is there anything I can do to try to debug this or are there any
tricks to either debug or solve this?

Oh, and is there any support at all for finding out the 3ware status?
It would be nice to know if a drive fails but 3dm is marked i386 only.

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