Do cats have memories??of people.?

i had my two cats from kittens for 2 years when moved couldnt take them with so neighbous took them that was 3 years ago [nearly].will they remember me .or is it tones in your voice they reconise?please help.as i have recently seen one of them and it was very sad when i had to leave them he just seemed a little weary,so dont know if they can actually remember people??thankyou hope to get some anwsers soon,haley