I am getting the warning as well on an Abit AN-M2HD with an AMD 64 5400 . Somewhat worse though since it actually does lock up the virtual machine instance of OpenSolaris. I am using the binary version of VirtualBox because I was not able to get the OSE version to compile.
SunOS truth 5.11 snv_95 i86pc i386 i86pc Solaris -- This message posted from opensolaris.org