Question concerning Duo Core 2 by Intel

My roomie and I both have the same computers with the same specs---Dell XPS 410---the only difference is mine has a Duo Core 2 and his has a single core---i guess it's a single---it's not a Duo---can someone please tell me the difference?---he is quite the gamer---his computer seems just as fast as mine but would it be to his advantage to upgrade his to a Duo?---I am quite ignorant on this stuff---so a very simple answer about the differences would be deeply appreciated!---lol---thanks in advance---DJ

 

DomLuc---excellent website you sent us to---thanks much!