Sony的理由有二
1. Of course, this begs the question: why? Why would Sony choose to
cripple their own hardware? Well, the most obvious answer is that
they needed to maintain an acceptable battery life. In the lead up to
PSP's debut, it's battery duration was often quoted as it's single
biggest potential problem. Had they launched the PSP with games
running at a fully unlocked 333Mhz, the battery could have been dead
in less than two hours. That just wouldn't do. Through capping the
PSP's clockspeed (and enforcing other power-saving guidelines) Sony
have achieved a respectable 4-6 hours of gameplay from a single
charge.
2. The current performance cap may have other benefits in the long
run. Rather than letting developers wastefully chew up the whole of
PSP's hardware capability from the get-go with inefficient code, the
restrictions essentially force them to code more efficiently from the
beginning. Consequently, when the ceiling is eventually lifted, the
developers will be ready to put the extra power to good use.