I did observe similar behaviour on four X4100 M2 as well (two with one socket dual-core, two with two sockets dual-core Opterons) using amd64 bsd.mp snapshots from 23 and 28 Aug..
Currently, amd64 bsd.mp snapshot 28. Aug is running stable on those four servers, although using a single SAS disk without RAID. Several days ago, there was a commit in kernel CVS about delaying start of IPMI which is causing annoying delays at startup of amd64. Eventually, a more recent snapshot becomes available which includes this modification, before I get around to build a -current kernel. Rolf
