O & O Defrag from O & O software is the best that u can get for Defragmenting your Hard Drive. It provides a lot of options for defragmenting that u won't find in the Windows Defragment or any other software. Try it once for 30 days using the demo and you won't be disappointed. It claims a performance increase of upto 30% although I have not measured it but it does improves uto some extent, some magazines have reported a performance gain of about 27% which is not bad. Try it and post ur suggestions, If u know any other software that can outperform O & O than please tell.