Without knowing exactly what two drives you're comparing, I can't give you a clear answer. But it still sounds like you're deciding that the temperature is the

Without knowing exactly what two drives you're comparing, I can't give you a clear answer. But it still sounds like you're deciding that the temperature is the cause of the performance difference, without having any evidence to rule out the possibility that the your temperature and performance observations are two different consequences of an underlying hardware difference between the two different drives.