Originally Posted by itz.clint
With rads water is cooled as it flows through them multiple times circling in the loop, from what I understand going from a rad to another rad is a waste since it is outputing delta temp waters from one into another then to your pump combo. It is understandble going from your rad> res combo to rad then cpu through loop etc as that gives your cpu the coolest water as it isnt warm from the pump motor hope it makes sense.
Practically every radiator on the market ( Except for the Aquacomputer ) are simple U flow dual pass rads. water flows down tubes on one side and back up on the other side. Slim rads have one row of tubes and thicker rads have two or three but they are just simple U flow still. The extra tubes of the thicker rads just reduces restriction because the water has twice or three times the number of tubes to flow through.
The order of components in a loop, as long as flow is reasonable, has very little impact on temps. The temp increase between components is usually less than a single degree but the whole loop increases by something like 10C over ambient or even more. Radiators only work if the water in them is warmer than the air going through them. They do not return the water to ambient temperature or even close.