You might copy a set of digital folders from one folder to another; accidentally download the same file twice; or save an important document in two or more places on your hard drive. These events all sound harmless enough, but if you don't notice what you've done then you may have created unnecessary duplicate files that will tie up hard drive space, and slow down operations like virus scans, searches or defrags.

DupKiller can help, though, by tracking down all these duplicates for you - and fast. Other duplicate finders we've tried take seemingly forever to come up with a useful report, but DupKiller searched more than a terabyte of data, over 300,000 files, in a little over five minutes. If you're the impatient type then this program is definitely worth a try.

Of course, as with all similar programs, it really doesn't pay to be impatient once you've got the full DupKiller report. On our test PC this returned no less than 10,829 sets of duplicates files, occupying a sizeable 12.78GB of hard drive space. But some of these were drivers, DLLs and other important files, which were best left alone. And in other groups you must manually decide which file to delete, still a risky business it you get it wrong.