One of the best disk defraggers out.. 

The PerfectDisk Difference 

Certified by Microsoft for Windows Server® 2003 and Windows 2000 
Designed for Windows XP - Optimized 
Designed to defragment large and complex environments that other products can't 
SMARTPlacement? - Patented optimization strategy - to reduce time and resources consumed for future defragmentation runs 
Defragments files in a single pass 
Single pass consolidation of free space to slow the rate of refragmentation 
Requires as little as 5% free space 
Perfect Management? technology provides integration with Active Directory for powerful and flexible enterprise management and scheduling 
Automatic scheduling of defragmentation runs across the enterprise 
Works seamlessly with PerfectDisk for Exchange to automate the offline compaction/defragmentation of Exchange data stores 
Perfect-Time? threshold capabilities for enhanced automation 
Full-featured command line options (local and network) to accommodate unique environments 


What's new in PerfectDisk V8: 
? PerfectDisk Command Center management console for deploying, configuring, scheduling, managing, and reporting on the enterprise 
? Patent-pending Resource Saver(TM) technology 
? Graphical displays to track performance statistics, fragmentation and drive usage over time 
? Statistical displays showing the number and size of files, by file type 
? Enhanced flexibility with AutoPilot Scheduling(TM) 
? Screen Saver Mode (Professional version only) 
? Single File Defrag 
? Consolidate Free Space Defrag 
? I/O throttling 
? CPU throttling 
? Automatic shutdown after defrag (Professional version only) 
? Power management for laptop users and users connected to UPS systems