Consensus on 4820TG vs. 3820TG's temperatures/cooling?

Hey all,

Been a while since I've passed through the Acer section on NBR

Just wondering, what's the consensus on 4820TG vs.
3820TG in terms of temperatures and cooling? Is the 13in model cooler cuz of dual fans? Does the 14in model even have 2 fans?

And for kicks, if anyone has the info on hand, how's the 5820TG compare with regards to temps and cooling?