Quick tip, open another window - doesn't matter what - over Hitfilm and tracking suddenly speeds up by a factor of 4-10, as it stops refreshing the screen, but is still running behind. It doesn't even need to cover the whole screen, so you can still see the little tracking bar whizzing along, and can periodically shrink the extra window to check it's... on track...then pop it back up again to carry on at top speed.
Makes tracking .MP4 files (which are fine to edit with, but deathly slow to track; e.g. 1 frame a second) actually manageable. It also speeds up other files types, but by a lesser amount, as they're already handled better.
Does seem to illustrate that the drawing of the dots and updating the console info takes up a lot more time than the actual tracking.