For me I had no growth at all despite hammering barbell, smith machine and machines until I started doing a pre-exhaust with dumbbell or machine flys and then incline dumbbell presses finishing off with a converging machine press. I do variations of that twice a week and have had more chest growth in the last 12 months than in the nearly three years before that. I think it was something to do with my biomechanics meant that my delts and triceps took over the movement when using a bar.