Radiator connection too small?

I am looking at purchasing this radiator.
http://www.frozencpu.com/products/5...l_XTREME_Quad_480_Radiator.html?tl=g30c95s667
However, the connection is only a G1/4" thread. Why would they have such a small connection, if this is a "extreme" cooling radiator? The tubbing that is going to be on my computer is much bigger.
I understand that there are 'adapter-connections" connections for it. But, I want more liquid to be flowing into the radiator.

I am just curious. Thanks for your time

The G1/4" thread is the most common thread type. 90% of all water cooling componets use the G1/4" threads, apart from Thermochill and some EK products.

the faster your pump the more liquid will flow through, the fact that its at a smaller tube size just means it'll be flowing through it faster. wide river versus narrow river, which one has more water flowing through? well, on a technicality the same amount flows through per day just at different rates of speed.