Intensity trumps volume when it comes to building fitness.
The definition of intensity from the Journal:
"Crudely translated, it means this: Do more work in less time—not more work in more time.
Explained via a CrossFit scenario, if you took 10 minutes to do Fran and then did another workout because “10 minutes wasn’t enough,” you did not perform Fran with intensity. If you had, you’d still be on your back. Likewise, you will not reap intensity’s benefits."
Those of you who have performed the workout Fran (reps of 21, 15, 9 of thrusters and pull ups) with intensity know what this feels like. Now, this doesn't mean going fast at all costs. The CrossFit prescription for development is still technique then consistency and only then intensity. That means you have to learn the skill of the movement and perform it well and increasingly often, then you can start adding intensity (speed, weight, larger ranges of motion).
You've probably noticed more info on proper pacing when we go over the workout with you. These concepts are important and you're going to hear more of it including more time markers like those mentioned in the Journal article.
Maintaining that high intensity (provided your technique and consistency are there) will get you fitter faster than insisting on doing the workout as prescribed before you're ready and taking longer to complete the work, which is what (I must confess) I was apt to do. I now call that hiding behind heavier or harder movements. Don't hide. Show us your skill, demonstrate you can handle the volume and then we'll let you go as fast as you want.