Currently, the psp is running at 222MhZ which is 2 thirds. This is not becuase of the games or the firmware but because of the battery. At time of the release sony only had developed a battery that could run for a couple hour at 333MhZ. I have heard about recalls of all psp's and will be sent a new stronger battery, but you wont get any higher life. The reason that they wouldnt make you buy the battery is because they did specify that it was running at a lower speed.
This is news that has recently been found. But I'm pretty sure that we will see games that are better faster and stronger in the future with know charge to us. The thing that it would most improve would be the load times which at this time, is the worst thing about the psp.
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