While it is freeware and open-source, it's nothing spectacular and the basic display view is less than can be desired. I'm not even positive on what sort of file placement (if any) it does after simply defragmenting files. I've recently realized the importance and necessity of having file placement done after a defrag. I have 3 screenshots that prove this, which anyone can do themselves. Disk Analyzed http://img338.imageshack.us/img338/9590/ud1dw5.png Disk Defragmented Completely http://img338.imageshack.us/img338/3064/ud2ag1.png File Placement (79% of least used data placed on inner tracks and 21% of most used data placed on outer tracks + Consolidation defrag) http://img338.imageshack.us/img338/418/ud3lc7.png As you can see, merely having the files defragmented only does half the job. At this point there is still much room for future fragmentation and access time is nowhere near being optimized. And by optimized, I mean having files related by either last access or modification date placed together at the beginning of the HDD inwards. Having the most used data at the beginning of the disk and the rest of the files out of the way on the slower areas of the disk improves file access time (truthfully by milliseconds, which in reality leads to several seconds of application and game loading). Then comes the Consolidation method which places files sequentially and thus contiguously (no gaps in between any two given files). This creates the largest area of free space after the most used files for new files to be written. The file may or may not be fragmented when written to this free space, but it won't be fragmented nearly as much as it would be had it been written to a severely fragmented (and non-contiguous) drive where there were many gaps to fill. Diskeeper is automatic and does file placement, but not always necessarily consolidated. You can defrag with any defragmenter and use UltimateDefrag to view the disk display and see exactly where and how files are placed. PerfectDisk isn't as automatic, and does do file placement in the same manner, thus future fragmentation is reduced. UltimateDefrag offers the most flexibility and shows a true drive display and is portable (1 EXE and 2 XML files on my flash drive). I hope this helps. Does UltimateDefrag support Vista Home Premium 64bit ?