You can tell if it's optimized (even with the windoze defragger) by looking at the graphic report. If optimized, you'll have one or two big chunks (I can never remember if they're blue or green) to the left of the windows defragger graphic (i.e., the front of the drive), and white space to the right. Windows will take out the red fragmented files, but may leave chunks of contiguous files all over the drive that will look like slivers spread all over the graphic.
Some would say it doesn't make that big of a difference, but I believe I see a speed increase on file access on a well defragmented drive.
It can make a difference, especially in applications that use many large files, such as games (what with textures, music, sound and level data, )
A true optimization program would have related files contiguous to each other, I.E all windows files together, all office files together, all game files, whatever.
