FYI, I've completed this family of PMP-450 curves to give you a better sense of the overall differences between the PMP-450 and PMP-450S:
If you're shooting for the 1+GPM mark for flow on a low restriction CPU only loop, you can see that a PMP-450 on Setting 3 is adequate and would only consume around 9 watts in power. However in a multi CPU/GPU/MB high restriction loop the PMP-450S would almost get there and would draw around 30W.
Also the PMP-450 at 16V is actually a fairly good balance between pumping power and power consumption. It's only consuming an extra 4-5 watts and acting like a setting 6 of sorts. There is however different RPM reduction going on. The Strong has a slightly steeper curve set when below 20 Volts.
There is a lot going on here, but with some practice it can be put to use..Edited by Martinm210 - 2/14/11 at 6:30pm