Interestingly enough I just took the fan off and put the Gigabyte plate back on . The IOH temp went up to 47c . With the plate and fan 42c . With the fan and no plate back down to 36c !
As wolvers69 noted the temp difference between idle and load doesn't change much . For mine 1 to 3c maybe . Seems to depend on ambient temp .

@lsd
j