Im using MSI kn9 platinum and geil GX21GB6400DCK 1 gb kit and both the mobo and ram are spec'd to 1.8 v. I stick it all together and defaults to 1.9 volts. Why? Im not OC.
Assuming you are seeing the 1.9V on your BIOS (or utility software in Win) voltage readout (NOT setting) section, don't worry about it. The builtin temp/voltage monitors are not that accurate.