well you mentioning it being quiet while being a great preformer tickles my fancy since all the cars i lay lay my hands on sound like chubbaca heavily breathing , so i'd love to win it !
i would suggest taking it to a shop so you wont regret your doings if you failed .thats pretty true and also cleaning the fan and heatsink would be a good idea !
is there a new app that you have istalled that requires notifications or something ? also check how much storage space you may have left and clean the unnecessary sometimes just to calculate it stops everything