You start hitting diminishing returns after +26 speed; from that point on each additional point of speed gives you less and less extra energy per game turn. For example, +10 is 2x faster than normal; +20 is 3x faster; +25 is 3.5x faster; +30 is 3.8x faster; +40 is 4.2x faster; +50 is 4.5x faster; +70 is 4.9x faster, and that's where it maxes out. As long as you can get temporarily over +30 speed, no monster in the game can doublemove you, and that's the most important thing.
