If you’ve ever tried to transfer large files between a computer running Vista or
Windows7 and another running Windows XP you may have noticed it can take
a long time.

This problem is caused by a Windows feature called Remote Differential
Compression, a tool used to conserve system resources during network
transfers.

To turn off Remote Differential Compression, click START and type features.
Second on the list that appears is Turn Windows features on or off. This brings
up the following window.

Scroll down until you see a tick box for Remote Differential Compression.
Untick it and press OK. Select yes to restart your system.

You should now see a substantial improvement in transfer speed.