Take it slow. Learn to master slow tempos first before going faster. try playing with a metronome at 60bpm and first play 4th notes, then 6th notes(triplets) then 8th notes then 12 notes then 16th notes...etc... try to get 'em REALLY tight and confident. Speed comes from control and balance. think of sitting ON your ass. so that you feel a kind of a pressure on your ass when you'd play on a wooden stool for example. Maintain that(good balance).
Speed comes slowly, don't think about it. Just try to play some fast shit and someday it might start coming! I tried to play Rotten Sound's murderworks for like 1,5 years before I nailed it BADLY. Nowadays I can (about 1,5 after...) nail it pretty well but not half as well as kaitsu

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the point is: concentrate on the music, not the speed. Speed will come eventually if you haven't got any too bad habbits. Keep grinding!