Ben-DutkaUpdate: This rumor is, as far as we can tell, entirely false. With the patch being out, nobody can confirm that the feature outlined below was unlocked.
The firmware updates have arrived on a fairly consistent basis for the PSP, and it seems the next isn't far away. According to an industry insider via QJ.net, the upcoming firmware 3.50 brings one very important feature to Sony's handheld: it will allow commercial games to run at the PSP's full 333mhz CPU speed.
Thus far, all UMD-format games on the portable have been limited to a 266mhz – although most every one only plays at a 222mhz speed – which is only 80% of the portable's full power. The benefits to having games run at full capacity? Well, this would mean (theoretically) accelerated frame rates and faster load times for starters, but the future is even more intriguing with this update. Perhaps Sony will take advantage of this by switching off the proverbial limiter on the PSP, which could eventually lead to a new battery.
However, bear in mind that this is nothing more than a rumor. While firmware update 3.50 is certainly coming, Sony has not confirmed the feature outlined here. We'll be sure to update you with the full details when we know more.