Psp gaming problem

when i open a game on my memory stick its loading is too slow,even when the game starts the characters are moving in slow motion,that makes the game quite dull,i thought maybe only the games that are save on my memory stick are the only affected,so i try to use my UMD which i was really often using before i had no save games on my memory,but still when i load it,it was also affected,it loading is slow,and the also the movement of the characters, which before was not...why is it so,is there a problem to fix on my psp?