yeah, defrag it. Should take no more than 30 min with a good defragger. Also helps to run ccleaner for a disk cleanup before the defrag so you don't end up having to defrag useless files.
A defragmented drive not only prevents performance loss, but may extend the life of the drive over the long term, and also increase the chance of recovering files in the event of a drive crash. So, it's good to keep fragmentation low. In my case, I never see a pic like above because my defragger is automatic and does a good job in the background.