I don't know if I can play as fast as you (I don't use a metronome which is foolish of me) but I wonder if you are using too much wrist and too little elbow. Some players play all from the elbow, some all from the wrist. Most mix it up. All wrist sounds painful to me but I think (from what I have seen of Malmsteem) he's mostly a wrist player but it's hard for me to tell from what little I've seen. Be careful that you don't injure your tendons. I used to be a wrist player but I didn't do it right and it was a real strain. If you want to pick up speed I suggest you work on your sweep picking, bursting up and down in pitch rather than repeating the same one sounds faster to me anyway.
One more thing: use a chunky plectrum with tapered to a point. Thin plectrums bend before they pass over the string leaving you waiting for the point to pass, the time involved isn't very great but it is important if you are a speed player.