Drive usage lower than it should be?

The image shows the drive usage.

I know that the load can reach 300 MB, but it only happens occasionally and not all the time, which significantly slows down the download. I've never really paid attention to it because until recently I had an 8k connection. But now it's really bothering me because I've already downloaded everything, and it takes a while to finish. I also have the feeling that this is also slowing down the download somewhat.