New Super mario Bros is litterally one of the easiest games to emulate. Try the Last Story, Rogue Squadron, or Xenoblade on that machine and report back about how bad performance is 
Question 1: why do you want a passively cooled computer?
Question 2: Are you looking for something low powered as well? if so, why?
Edit: the J3710 isn't a horrible CPU, but it has a base clock of 1.6 GHz, and a max boost of 2.6 GHz, so you'll probably have trouble playing some games.

Question 1: why do you want a passively cooled computer?
Question 2: Are you looking for something low powered as well? if so, why?
Edit: the J3710 isn't a horrible CPU, but it has a base clock of 1.6 GHz, and a max boost of 2.6 GHz, so you'll probably have trouble playing some games.

