Check in Task Manager to see what program is actually using the hard drive.
Anecdotally, I grabbed a few Lenovo Yogo from work when they were getting rid of old laptops. They kept and destroyed the hard drive, and I made the mistake of buying the cheapest, slowest, spinning-type drive. It's got a ton of room, but man is it a slow dog. I really should have opted for an SSD, at the very least a hybrid one so the OS could be snappy.
As for some great suggestions: I'd recommend this great page by another MVP. I went through it this weekend trying to improve performance on an HP Stream laptop (a terrible device with only 30 GB of total drive space, yuck). https://www.tenforums.com/tutorials/26120-optimize-performance-windows-10-a.html
Some of the things I did was disable indexing (it's used as a "email and web only" device by my parents, so there probably wasn't anything to get indexed anyway, but I still disabled it). I also turned off superfetch (which also probably doesn't make much difference for speed since that computer DOES have an SSD drive, but I still turned it off regardless).