What is the use of a quad core ?

i recemtly replaced my core 2 duo processor with a quad core q6600 ,but except for higher game rates in games like crysis warhead ,and gta 4 i dont find any difference in day to day work ,i am not a gamer but i do like to have a ga,img pc so although i have a nvidia 9600gt ,quad core ,4 gb ram ,500 gb hard disk ,all the parts like the ram ,the hard disk are of chinese cheap brand so well honestly just get around 40 fps in crysis warhead on enthusiast with no aa and a resolution of 1024*768 ,is there any other use of the four cores except multi tasking (which i dont have to do usually ) and gaming