Excessive Broadcast Traffic

I have just deployed Vista Enterprise to over 400 systems in one of our
computer laboratories. Since then I have noticed an excessive amount of
broadcast traffic coming from this segment of the network. I have put a Fluke
OptiView on the switch stack and can see that it is ARP traffic (all
broadcast). I can not determine where it is going (I have not put a sniffer
in line yet) or what the packets contain. Does anyone have any idea why Vista
would be so much more "chatty" than XP and are there any solutions to
minimize the boradcasts?

thanks,
mitch