Terrible Glitches in sound in song

Hi i am having terrible glitches in song to a point it becomes impossible to edit anything in realtime.
I am using an external card which i thought would solve the issue?

Is there a way to avoid the glitches?

I am having 100 bars and 22 band changes. (is that the root)
If it is the root, how is it possible to compose a song longer than a minutes that has a lot of breaks?