[Cathar]

Originally Posted by Blackeagle

In so far as the amount of power used, and heat added to water, I see what you are driving at Cathar.

But 2 X 50Z => $160.00 USD + 30$ for power adaptor........and if you need a separate PSU to run the dual pumps, or just a bit larger & higher quality PSU to be sure of all working well...$$ more. So while the 2 X 50Z @13.8v will perform, they also cost at the same level as the MD30, or depending on PSU extra cost.......even a bit more.

The above is getting expensive quick. At this point the MD20Z is looking better when costs of such set ups are factored in.

I would really only recommend the single AquaXtreme 50Z @ 13.8v, and not dual pumps. The differences between the two really is quite small (negligible), and certainly not worthy of getting a second pump.

The 20RZ is actually a lesser performing pump. I ripped those two posts at the start of this thread out of an evolving thread with little or no editing. The 20RZ I would not recommend over a single AquaXtreme 50Z @ 13.8v. I would only recommend the 20RZ in a DC powered format, which sadly doesn't exist, yet.

I apologise to all for the confusion. The statements in the second post of this thread are meant to over-ride the statements from the first post. I see that this is causing some unintended confusion.

The estimate you used for the 4 X 12cm fan rad seems to sell the core short of what I would expect of it. But such are estimates. And I understand you used the 120.3 figure as it's a solid set of numbers for the comparison. But a higher performing rad would reduce the pump heat effect of the larger pumps more. I'll have one before much longer, then I'll have a chance to see how good it is.

Sell it short? How so? I have and actively use a 12" x 10" radiator here. I use 2 x Panaflo L1A's on it at 12v and estimate that my radiator's C/W is around the 0.020 - 0.022 mark with ~33dBA noise (based on manufacturer fan noise ratings).

Estimating a ~0.02 C/W with tolerable fan noise levels is not selling a 25 x 25cm radiator short at all, unless you desire to wear ear-plugs while computing. I would estimate that accounting for the radiator's inefficiencies you would need to be pushing at least around 150CFM through a quad fan radiator to achieve the 0.015 C/W figures I atrributed to it with strong fans. I assure you that achieving 150CFM through even such a large radiator with tolerable noise levels is not as easy as it may seem. Can always achieve quite fantastic radiator performance so long as noise is not part of the equation.