One of the things I didn't know about the Sony PlayStation Portable is that these handheld gaming consoles use an underclocked processor. DailyTech reports just about every single PSP game runs at 222MHz while the MIPS R4000-based processor inside the CPU has a clockspeed of 333MHz.
It's not sure why Sony decided to underclock the processor but most developers believe the company did this to improve battery life. One of the surprising new features of the latest firmware 3.5 update for the Sony PSP is the ability to unlock the full clockspeed of the PSP. Game developers will now be able to utilise the full 333MHz:
The PSP’s newly unshackled abilities do not affect already released games, however, as the speed increase will only be realized and utilized in games that specifically call for the CPU’s top speed.
While licensed software hasn’t pushed Sony’s handheld to 333MHz, modified firmware has. Software released by PSP modders allow for homebrewers to set clockspeeds to 333MHz, resulting in smoother framerates, but at the expense of battery life.