[airspirit]

There will be almost no resistance from the T junctions, as I will be using 1.5" PVC. The radiator will be on the straightshot from the res, with the side branch going to the bypass. It will be the same on the other side. The flow will be optimised to go through the radiator. Everything from the res to the pump will be a minimum of 1.5" in diameter (except the rad, of course) to prevent undue flow restriction. Between the pump outlet (3/4") and the res there will be 3-4 3/8" lines with one waterblock on each. Really, the point of greatest restriction in the loop is the radiator. I'm not saying this will work for everybody. This may help for MP users wanting psycho flow. This will help my system, without a doubt.

Even with an overkill pump like the 1200, I may be restricted to 3-4GPM max system flow if it is straight inline, leaving less than 1GPM per block. That is unacceptable, especially since at least one will be on a very high temp chip (my current XP chip is at 2V and 1880 Mhz, and the one that I will be picking up next month will be worse). In order to pull the heat from the block effectively, I will need more flow that 1GPM. By using the bypass it is obvious that my water temps will rise somewhat. The water that passes through the radiator will be cooling the water more efficiently, however, recovering ground somewhat. Overall, though, it is plain that the overall temp of the water will find equilibrium at a higher temperature than if the bypass wasn't used.

What is the question, is whether doubling the flow through the blocks with slightly higher temperature coolant will cool them more effectively when they are at peak output. I suspect that the answer is yes. When all is said and done, I will do some Poor Boy Benching of the idea. I will hook up all the machines and let them idle with all the coolant going through the rad for one hour. This amount of time should cause all the coolant to go to equilibrium temp. Then I will open the bypass little by little over the course of a couple days to measure changes. Then I will do the same with them all running crazy benchmarks and see what happens. If anything, it will give good (if non-scientific) data to demonstrate if this works or not.

I don't know ... if anything, there will be minimal head loss from the bypass loop, as it will be splitting off on the perpendicular arm of the Ts used, preventing any head loss from the joint (which would be minimal anyway since it will be a 1.5" joint). The worst case scenario is that I just leave the valve closed all the time. I do not think that will be the case, however. I haven't seen any hard data that can prove the concept otherwise. It only makes sense that if you utilise all the components as close to their "Max gain per effort" point that you will get better temps overall.

This will be an interesting experiment. The radiator is on a UPS truck from Spokane and my hose is stuck in Hodgkins IL, and I will probably be ordering the cases and pump later this month (I hope the wife doesn't read this!). Once I pick up a new board/proc/ram next month (Prolly Chaintech NForce2/AXP 1800+ TbredB if avail./2x256 XMS2700), it will be less than a week before I have the data for you.