There are plenty of downloadable defrag utilities to choose from, but it's hard to beat the ease of use and helpful extras in IOBit's Smart Defrag.
With this utility you can quickly analyse your hard drive to check the level of defragmentation before committing to a scan. The interface shows you different coloured blocks representing fragmented files, frequently used files and more, with a helpful key to show what each colour represents.
When you're ready to pull the trigger, you can choose from a straight defragmentation (fastest), or have Smart Defrag perform either a fast or "deep" optimisation after defragmentation. Our test machine had a rather full hard drive, so even using the fast optimisation took close to 40 minutes. Depending on your hard drive and level of defragmentation, your mileage may vary.
In addition to the solid defragmentation tools, you can have Smart Defrag automatically defrag the files you use the most without significantly slowing down your system. Even while performing a full defragmention and optimisation run, the program barely uses as much as 25MB of RAM, and with just the auto-defrag running continually it uses about half that amount.
Smart Defrag offers a few extras, including a scheduler so you can set it to only defrag during downtime. You can set it to run scans on bootup or even have the app shut down your computer when it's done defragging selected hard drives or partitions.
It's important to note that Smart Defrag is not as essential for those running Windows 7, because the OS defrags continually on its own. But if you run external drives connected to a Windows 7 computer, this utility will come in handy for keeping the external drives running smoothly.
Overall: if you want a quick and solid defrag utility to make your computer run more smoothly, plus added options for scheduling and other extras, you should definitely download this program. Both beginner and advanced users will have no trouble operating such a solid utility.