You've misunderstood the nature of the "FPS cap." The FPS cap isn't a "performance issue."
There are two independent components for FPS -- the actual graphics processing, and the display. Before, regardless of the processing, the display was being limited to 30 fps. Now that is lifted, so to the extent, our graphics processing can handle more than 30, it will display it.
However, this does nothing for the graphics processing, which the Evo is known to not be the greatest at. The Droid X and Samsung phones have much more advanced 3D processors than the Snapdragon/Evo, and this update does nothing to solve that.