Instructions
Acquire a different memory card. When encountering lags during gameplay, you may find the lagging can be due to something as simple as faulty memory. For instance, making the upgrade from a 4 GB Sony PSP memory card to an 8 GB memory card can make a huge difference in playability.
Ensure that your PSP's memory card isn't too near to its capacity as this can often affect how smoothly your console runs. If you are verging on filling your memory card to the brim, it may be a sensible idea to perhaps remove some unecessary saves or items from your PSP to help it run more smoothly. It should also significantly lessen the lag you may have previously experienced playing "Grand Theft Auto: Vice City Stories."
Adjust the "Grand Theft Auto: Vice City Stories" in-game settings by pausing the game and selecting the "Display" option. Scroll through to the game's graphics settings and lower them slightly. You may find that lowering the game's graphic performance and display ratio will improve gameplay and reduce or eliminate lag.