The usual reason why clicking a button results in a significant delay before it gets to the destination slide is that Captivate is trying to render all slides in between so that it can make sure everything is set up properly before loading that slide.
So my questions are:
- If your project is 40 meg when published, what is the total playing duration?
- How long on average is each of those 37 slides?
- Is the delay noticeably shorter if you jump to a slide closer to the button slide than if you jump to a slide a long way further down the slide order?