I've been trying to use bandicam to record my play through of some songs but when I go to watch the video it just looks a little laggy to me. It looks like the notes scrolling across the screen are just a little out of sync from the sound sometimes. How would I go about fixing this??

maybe try the 'action cam' by mirillis, it needs less processor power. I also recorded with bandicam before and as I remember I had to turn down everything from resolution to all game effects to get a fairly fluid recording. Then I changed to Action Cam everything seems better to me there. But it's only 30 days free.

Bandicam is actually my fav.  I'd try lowering quality settings to get more fluid recordings.

 

Also, if your pc is not running at constant 60fps even without recording, then recording with most programs will kill it.

 

I've never tried Action Cam, so cannot comment on that, but OBS (Open Broadcaster) is very highly thought of around here.  Good quality recordings for low overheads.  You could look into that too.