Well, speed comes with time. Pratice with a metronome, and increase notch by notch when you can play it cleanly. Write down the BPM you have started at. You'll be surprised if you are dedicated. By the way, overworking can hurt you, so if it hurts/burns, stop immediately, come back a few hours later.
Petrucci has worked a lot this way, so be patient, anyone can play what he comes up with, but only a few can come up with what he comes up with.