This is just what the game does. It assumes people use Win98 in which if you DIDN'T use 100% of the processing power in a full-screen app, bad things would happen. This is still more-or-less true, but not of FF7. It doesn't require all it locks. Indeed, it WILL try to lock an entire processor core for its dedicated use. There might be a way to prevent that, or at least throttle it, but I haven't investigated it too much.
Frankly, it's not really pushing your processor that hard, but it is counting ticks to determine game time and such. In that way it wants to catch every tick, but it's not really pushing it. Also, don't try to be using processor power while running FF7 (like defragging or installing something) for that reason.
Moral is: don't worry about it. There's probably nothing anyone can do about it without seriously re-writing the timing scripts.