A few days ago I've tried O&O defragmentation and this software ROCKS! My loading times are increased big time and it's therefore highly recommended; it can defrag in different ways, it totally 'rebuilds' your HD on name, on modified files, in stealth mode etc. and is extremely fast, (except when it has to move large files) and only a small minimum of HD space is required (as big as the biggest file on the drive). It has a nice gui where you can see what it is doing with your HD. You can download a 30 day trial to test it yourselves.. so do it Da link: http://www.oo-software.com/en/products/oodefrag/