It was a response to me playing pvp at 40 fps by someone who's watching over my shoulder.
If those slowdowns occur often then, yes, there is something wrong with your setup. If it happens only when the game is reading something from the hd then it's normal. By normal I mean that it's a known issue that hopefully will be resolved. There's always slowdowns when a game tries to read from the drive. Even in single player games. In tor it seems a bit more noticeable and, most importantly, for some reason it doesn't benefit from a fast drive.