Windows Vista operates external hard drives that are connected with USB differently than internal drives. Write caching is disabled so that you can safely remove the drive at almost any time.  This is a great feature for USB thumb drives that are frequently inserted and removed from your computer.  But if you have a large hard drive that is in an external enclosure that you never disconnect from your computer, write caching is also disabled which can decrease performance.

This tweak is going to show you how to increase the performance of your external hard drives by turning write caching back on as well as activating advanced performance.  Let’s get started:

1. Click on the start button, then right click on Computer and select Manage.
2. Click on Device Manager on the side menu.
3. Expand Disk drives and locate your external drive from the list.
4. Right click on the drive and select Properties.
5. On the Policies tab, select Optimize for performance.
6. Next, check Enable write caching on the disk and Enable advanced performance as shown below.
   
   
7. Hit OK and reboot.

Enjoy the increased performance!