Water pump flow rate....
 

I know higer flowrate means more water going through the cpu block faster, but it also means less time in the radiator.

Would there be a large difference between 100gph and 300gph, or maybe a couple of degrees??

i consider a high flow rate to be more effective compared to a low flow rate system...so a 300gph would be cool!

My point is we should not make the water stay in the waterblock too long...