check here and you will known:
and here for a in house discussion:
The answer is depends on the rad. Is not that generic. In general thicker cores will render better performance but is not all that straight. Depends also on flow rate and fan configuration and speed. The best performers out there seems to be rads on the 50-60 mm thickness.
And if you like that review give Fast Fate a proper thanks with a +rep. The guy have done such a wonderful job reviewing the rads and I fell like he deserve more thanks from this community for it.
Edited by Gabrielzm - 5/16/15 at 4:47pm