What are some alternatives?
When comparing PerfectDisk and System Mechanic, you can also consider the following products
Defraggler - Defraggler, the award-winning hard drive defrag tool from the makers of CCleaner. Optimize your hard drive and free up space. Download the latest version for free.
BleachBit - When your computer is getting full, BleachBit quickly frees disk space.
UltraDefrag - UltraDefrag is an open source disk defragmenter for Windows.
AVG PC TuneUp - Peak performance for your PC. Keeps it going for longer. - More Speed Turbo Mode
IObit Smart Defrag - Disk defrag your Windows with Smart Defrag freeware, Your first choice for defragging windows 10, 8, 7, XP and Vista. Download Free disk defragmenter now!
Glary Utilities - The Official Website of Glary Utilities.