Any news on slow network transfers?

I ran some tests - between PCs - Vista to XP, Vista on a domain to a file
server. Both were significantly slower than XP to XP or XP to Vista. I
am using different vista machines that I have duplicate hardware for for
testing - so it is an apples to apples comparision in terms of hardware -
only differernce if Vista. I've made sure I'm using the latest drivers for
everything. I'm getting about 25% of the performance on Vista. I've
seen other posts with people having the same issue but I haven't noticed a
fix/solution yet. Hopefully this isn't going to say that way. I'm amazed
no one as MS said - hey, this is really slow in the beta stage. I signed
up for Beta but wasn't selected.