It sounds like SP1 fixes that particular issue.
Microsoft publishes detailed Vista SP1 “changelog” - istartedsomething* Improve by 25 % local file copying on the same disk on the same machine
* Improve by 45 % the speed of copying files from a remote non-Windows Vista system to a SP1 system
* Speed up by 50 %, the rate of copying files from a remote SP1 system to a local SP1 system