Certainly is, in my opinion. I've used Defraggler, but found that Auglogics Disk Defrag does better. You can get it here.
Download Auslogics Disk Defrag 3.3.1.2 - FileHippo.com
Once you get it defragged, you may wish to shrink your "C" partition to a more manageable size, like under 100GB. Mine is 70GB, & that's plenty. You can create another partition for data, to keep it separate from the OS. The purposes for this are twofold. First, your OS will run better on a smaller partition. Secondly, your data is protected from loss if your OS goes down. So, if you had to reinstall your OS, as we all have to from time to time, your data will be there.
Try out that software & see if it improves. It should.
Cat