Sounds like the problem is from accessing one of the drives, not from the OS or any other programs. Make sure MaxTransfer and DMA-mask are set correctly in hdtoolbox for the hdd that crashes your system. My SCSI hdd from my 1200 was unstable in my 4000T until I set the above mentioned parameters back to normal.
It could also be you are using some sort of file-system that doesn't work very well with a '030. If it is something other than OFS/FFS, it may be optimized for a specific processor.
