Diskeeper ($30, free trial) is more of a fragmentation-prevention and background-defragging program than a classic run-once defragger. The program's biggest problem is an interface that's seemingly designed to keep anyone who's ever used a standard defrag program from finding what they want.
Once you're used to finding the Analyze and Defrag options under Alerts and Reports, you'll find a lot to like about Diskeeper. Its Intelliwrite technology prevents fragmented writes and claims to speed them up; and the program includes automatic background defragging and S.M.A.R.T. monitoring, as well as I-FAAST, which monitors disk access and uses the acquired information to more intelligently optimize files when you next do a defrag. But while all of that is great for use on servers or high-end workstations, it's overkill for the average home PC.
That said, Diskeeper's hard-drive defragging was excellent and it gets even better over time as it learns. If you use an SSD, the program detects it and offers to optimize instead of defrag; alas, Diskeeper's optimize function took very little time and had little effect on the performance of our superfragmented test SSD...and by little, I mean none.
Raxco PerfectDisk Professional
PerfectDisk ($40; 30-day free trial) is an exceptional defragger. It uses a lot of intelligence (called SMARTPlacement) to place the most important files at the fastest part of the disk on a standard hard drive. It also runs at boot time to defrag system files (which are locked when Windows is running), and it initiates a background process to optimize drives in the background while your CPU is otherwise unoccupied. The background process is unobtrusive, at least on a decently fast PC.
PerfectDisk Professional is even more option-laden than Diskeeper, but you don't have to bounce around quite as much to find everything. The defragging tools are on the main page where they should be, and options are nicely organized into logically named dialog boxes. The program also features OptiWrite, which is supposed to keep fragmented writes from occurring in the first place. PerfectDisk tracks your drive's S.M.A.R.T. info as well, which is useful if you want to replace a drive before it fails: A rising S.M.A.R.T. error count might indicate an impending disk failure.
PerfectDisk did a bang-up job with my test hard drive, defragging and optimizing it in short order. And with an SSD, PerfectDisk—unlike Intelligent Defrag, Diskeeper, and Defrag Pro—actually spent some time with the drive. Nearly two hours, in fact. A jump of about 20 megabytes per second in the sequential read speed followed. This begs the question of whether two hours of sustained writes is worth a 5 percent gain in performance (one that you are unlikely to ever notice). For myself, and I'm guessing the majority of users, the answer will be no...but kudos to PerfectDisk for actually making a difference.
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