"Generic 120mm radiator with 3/8" OD barbs from BeCooling"
so tell me, that radiator, how much more surface area does that little thingy have over say a late model high performance heatsink....
There's your Sign
the only way water-cooling can be better than heatsink-cooling, is for the radiating surface of the rig, to be significantly larger than that of these heatsinks, note I say significant..... Why, because a liquid cooling rigs has on average 3 thermal junctions more, than a heatsink rig. ( CPU>>>Block>>>Water>>>Radiator>>>Air). Junctions are bad.
if not, then the water-cooling will have such a hard time being efficient though all these junctions, that it won't have time to do pretty much anything else... hens the crappy results...