Playing fast isn't everything, but it's something. It certainly isn't the measure of a great musician, but it is a skill great musicians of various genres call upon when needed. Fast tempos have generally not been my strength historically, but I'm still working on it. Here's an up-tempo practice session using CD Metronome and the chord changes of the tune Bebop. I think I started about quarter note=280 or so and went up to 360. My primary goals were to stay relaxed, play in time, keep it clean and melodic, and identify weaknesses and work them out in real time. I thought someone might find something useful or helpful here, hence the unedited upload. If you're at all curious, I'm playing a Daddario Select Jazz mpce, number 5, and a size 3 Nexus reed. Happy to answer any questions...happy practicing.