[Retric]

Your working from an overly simplistic model of cooling. The delta between the fin temperature and CPU temperature makes a huge difference in cooling efficiency. Two sets of fins may be moving the same amount of heat, but the CPU’s are at different temperatures due to differences in plumbing. Also, the way your working fluid flows through a radiator is a big deal, ideally you want the coldest part of the radiator on a return loop rather than heating the fluid as it’s passed to the CPU block.

Now, sure under ideal conditions and stock settings it’s not a big deal. But, in practice things get tricky.