I installed my DX48BT2 and Windows Vista 64bit service pack 1 yesterday, immediately I saw in the device manager that the SMBus controller had a yellow exclamation mark.

So I went to the Intel website and downloaded the chipset driver version 8.3.1.1010 and after restarting Windows the device disappeared.

If I right click the SMBus controller and check the properties, it says "No driver installed", however, if that was the actual case, Windows should still be reporting the SMBus controller with a conflict (!) and it is not.
I haven't see any pop-up configuration wizard asking for drivers since...

I'm a little concern about it, but other than that, my system is running like a champ, I had to work with Kingston to clock my memory at 1600mhz since later on I discovered that most of nowadays memory by factory defaults kicks at basic frecuencies to ensure POST.

Hope my experience helps you clarify something with the issue reported by nick DX48BT2...