When's the diminishing return on radiators come into effect?

[Kyzer]

45? 60? 80? (thick)

[W-L]

7 minutes ago, Kyzer said:

45? 60? 80? (thick)

It's not a simple answer, it has to do with many factors such as the fans used, the FPI of the fin arrays and what your cooling in your loop. 

 

In general however more rad space itself is always going to provide better performance over a thicker shorter rad. 

[Kyzer]

Just now, W-L said:

It's not a simple answer, it has to do with many factors such as the fans used, the FPI of the fin arrays and what your cooling in your loop. 

 

In general however more rad space itself is always going to provide better performance over a thicker shorter rad. 

its assuming same size and same fans.

[W-L]

1 minute ago, Kyzer said:

its assuming same size and same fans.

It still depends cause the FPI for a thick and thin rad can be very different, usually you see a much lower fin density on thick rads making it somewhat easier for the fans to force the air through them as they are thick so there is more depth for the air to pass through vs thin ones with a higher fin density.

 

What difference you see between a thick and thin rad is not a large amount, for example an ~40mm thick vs 80mm thick rad will not provide a doubling of cooling potential, it won't be even 25% more, at most maybe 10C if that. So there is not a huge performance boost obtaining super thick rads, but you still get more potential cooling if you have a fan setup that is well optimized for that specific rad. It's why the commonly suggested to get longer thinner rads than a shorter thicker one if possible for the most cooling potential. 

http://www.xtremerigs.net/2015/02/11/radiator-round-2015/5/

[Damascus]

Check out extremerigs, they do the kind of testing to answer your questions.

[kb5zue]

Given all things equal, point of diminished return would be when they start to leak.