I just used FRAPS for the whole demo, and I saw I was usually hitting 30fps, except for the tee shots, when I dipped into the teens. This seems like a video-card limitation, as I can't imagine the CPU doing much of anything at the start of the hole. My P3-866 + Xpert 128 actually felt roughly as smooth, though the demo defaulted to much lower graphics settings (smaller textures, more fixed camera angles).
In terms of consistently repeating a shot, the demo basiaclly boils down to timing your mouse strokes right for the most distance on the drives, as the ball will only fly straight. Putting isn't much harder. In fact, the demo didn't strike me as a big improvement (in terms of both graphics and gameplay) from the only golf game I ever bought, Sierra's FPS Golf. I haven't fired it up in a while, but I'm pretty sure I'll hit over 30fps consistently.