Killrob,
I have also read where many NIC cards will operate in modes that may not be expected when set in automatic mode. As i understand it, when this happens, it is a switch to NIC compatibility issue. Wish i could be of more help. Also there have been issues of the NIC cards being set when in automatic setting to half duplex.
Of course, all this is just a heads up on issues to be aware of by yourself or others.