You can overclock your PSP. The chip in your PSP was designed to run faster than it does out of the box. By default, the CPU runs at 222Mhz, but the MIPS R4000 processor was designed to run at 333Mhz with a 166Mhz bus. I don’t need to spell out for you what it means that the most powerful handheld gaming device is factory underclocked.
You may have noticed that some games start to choke in certain complex scenes, while the most complex game, God of War: Chains of Olympus (read our walkthrough) runs smooth as butter. Well, Sony allowed developers to change the clock speed from within the game, starting with Bios 3.5, which GoW takes advantage of. What about the other games that turn into slideshows? How do you unlock the CPU and get them to run faster?
The answer lies in a custom PSP firmware from team M33. With this custom firmware, you can do lots of neat things with your PSP, like run game backups, play UMD movie backups, run game cheats (by writing directly to the PSP memory), play homebrew games like emulators, and yes overclock your CPU. You’ll definitely want a 16GB Memory Stick after you upgrade your firmware.
Once you have the BIOS installed, you can install modules that let you change the CPU while in a game. All you have to do is press the Select button for a few seconds, and a menu will come up. You can then change the CPU and bus speed.
Changing the CPU on the fly is nice, but what if you want to make the Turbo speed your default? Well, once you have the new M33 BIOS installed, you have access to the Recovery menu, which allows you to change lots of default settings. To access the Recovery menu, hold down the Right shoulder button while turning on your PSP (it has to be completely off first).
Once in the Recovery menu, navigate to CPU Speed –> to be presented with a sub-menu. The two choices here are
Since the extra CPU cycles use up more battery power, then you might want to only overclock your CPU during games. Press X to cycle through the options of Default, 20, 100, 222, 266, 300, and 333. Once you are done, click Back to return to the main menu, and then Back to reset your PSP.
There you have it. When you run your games at 333 Mhz, then you will notice that nearly all graphic stutters and slow framerates are eliminated, even from the most complex PSP games.