IObit SmartDefrag helps defrag your hard drive most efficiently. The latest stable version can be found here.Majorgeek says: It's become almost common knowledge that the included disk defragmenter that comes with Microsoft Windows is not the best and never has been. You have many freeware replacements and SmartDefrag is one of the best. You can simply set it as your Windows defragmenter replacement and forget about it or you can go through the many options including boot time defrag. It's completely free and very easy to use as seen in the video below where we walk you through using it.Smart Defrag 4 is a FREE, light, and stable disk defragment tool designed for maximum hard drive performance. Based on IObit latest disk defrag engine and "Boot Time Disk Defrag" technology, Smart Defrag 4 not only provides defragmentation, like any typical disk defragmenter can do, but also intelligently streamlines your files based on using frequency, thus accelerating disk speed for faster data access! With the unique Deep Analyze technology, it smartly clean junk files before defragmentation to save more disk space for you. Being the first Disk Defragmenter that fully supports Windows 8/8.1 Metro Apps, Smart Defrag 4 works fast, automatically and quietly in the background and is a disk defragmenter suitable for large hard drives.