I have a GA-P35-DS3L (I curse Gigabyte tech support now for being lying a-holes) and a 2180, and the vdroop on that is pretty huge, too. I set it to 1.44v in the BIOS, and end up getting 1.348v actually getting to the processor. I don't think you should be too suprised by your vdroop, though.
There is a pencil mod out there to reduce the vdroop, though, if you want to try it. A quick google search should find it.