Dell Latitude Maximum RAM

I've been told that the official limit for ram in the Dell Latitude D830 is 4 Gb. I've also been told that the unofficial limit is 8 Gb when using a 64 bit OS. Anyone know the actual answer? Better yet, has anyone tried this upgrade themselves? RAM for this machine is old and very expensive, I'd like more RAM, but not if I have to return it because it will not work in the D830.