Ok I think I am done testing for the moment. Today I ran two separate tests (varying one parameter per test):
f(Vcore): where I ran the CPU at 2000MHz at 2.0, 1.9, 1.8, 1.7, 1.6, and 1.5V Core.
f(MHz): where I ran the CPU at 1.85VCore and 2111, 1757, 1407, 1231, and 1055MHz.
f(flow) was run last night with CPU at 2200MHz and 1.85V and flow rates were varied by progressively closing an inline ball valve.
Here are the comparisons:
It looks to me like the throttling of the pump results in a system that behaves a fair amount differently than adjusting CPU voltage or frequency. There also looks to be a noticable difference in behavior between voltage and frequency; guessing it's an issue of the "W" calc at the lower end of MHz.
As usual here is the data for Les:
http://www.procooling.com/users/phae...andmhzdata.jpg