Defragmenting your hard drive can make a real and significant difference to your PCs performance. So it's a pity that Windows' own defrag tool is slow, short on features and has a poor interface, especially in Vista. Fortunately there are plenty of free alternatives around, and IObit Smart Defrag is one of the best.

The program has a variety of defrag strategies, for instance. You're able to defragment files alone, defrag and compact free hard drive space, or use a "deep optimise" mode to reorganise your hard drive files for the best possible speeds. All work quickly and efficiently.

You're able to launch any of these defrag options on demand, on a schedule, or even in the background after your PC has been idle for a few minutes. We wondered if this meant the program would compromise the performance of other applications, but this really isn't the case. Smart Defrag needs less than 15MB of RAM, doesn't fire up until your system has been idle for 5 minutes, and stops as soon as other applications become active again, so it never got in our way. All you'll notice is an all-round speed boost as Smart Defrag fixes any defrag issues automatically, before they become too serious.

Smart Defrag also includes a "Boot Time Defrag" technology which allows you to defrag files during the system boot process - these are files that cannot be defragged or are not safe to move after Windows is running.