waterblock size

[john3850]

Why dont waterblock companies increase the wb size verticaly.
Every time I look at newer waterblocks there size just keep getting larger in reguard to there length and width while cpu dia.size gets smaller.

 

[QuantumPion]

For the same reason why heatsink fins are made as thin as possible. The waterblock is like the equivalent of a thermal pad, it is merely an interface between the CPU and the water. A thicker waterblock would decrease the heat transfer rate because it adds insulation.