When you are moving from Windows XP to Vista, you might find file transfers were much slower.
Microsoft release a pre-service pack update that addresses the problem and it seems to work great.
This update resolves issues that may affect some Windows Vista-based computers. These issues have been reported by customers who are using the Error Reporting service or Microsoft Customer Support Services.
By applying this update, you can achieve better performance and responsiveness in various scenarios. This update also improves the reliability of Windows Vista.
You can download from here