Partition Slows down my Entire Computer

I have a partition that is Mac OS Extended (Journaled).. It completely slows down my computer when it is mounted. It used to be NTFS (which is why it's called Windows) but I changed it.

It was working fine for two weeks, then suddenly it stopped working. This was once a major issue about last year. I stopped using the computer. But when I decided to come back.. suddenly the problem is gone. It's like it's a visitor that comes to annoy you for a couple of weeks and disappears, but you have to stay with them long enough to know when they leave..

PS: I verified and repaired all partitions. No issues.