Originally Posted by ChielScape
4.5/5.5 is the diameter, right?
with some hard numbers on the flowrate, you could calculate water velocity, which i think has more influence on temps than mere flowrate (as long as it remains in the good area...)
Yeah, actually the "Speced" 4.5 measures about 4.4mm. The hard part is you get some cooling by the base away from the nozzle. So with smaller nozzles, you'll probably still net higher velocities right at the nozzle opening, but lower velocities over the rest of the pin matrix.
Somewere along the lines the reduction in velocity through the matrix causes more harm than the good provided by the nozzle velocities at the center.
Just need to thoroughly test each nozzle and plot the curve to find the optimal point. Nobody has done that yet, and I'm sure it's different for every pump setup and every type of processor. That's just alot of work.