Watercooling dual CPU's: Series or parallel?

[Mingon]

I am getting another cpu tommorrow to go with my existing 2500+ in a msi k7d. It will be put into my machine (see sig) but I am asking peoples experiences/ opinions in putting them in either series or parallel.

Option1;

radiator > cpu > cpu > reservoir - this will maintain flow rate within the cpus, but second will heat quicker

Option 2

radiator > Y split > cpus > Y join > reservoir - this will halve the flow rate within the cpus (i think)

Option 3

radiator > cpu >buy another radiator > cpu > reservoir

 

[Ulfwald]

I have never done water cooling, but to me, common sense says to do in parrallel, you do not want the heat from 1 cpu carried to the other, this would reduce the cooling ability of the system. I would run 1 strong pump, split the pipes, to the water block in, the seperate pipes out of the water blocks back down to the tank. This way you relieve the stress on the pump, it does not have to push the water back together again. but if you do decide to join the pipes back together again on the downside, be sure to have smaller pipes feeding into a larger main pipe.

 

[MrThompson]

Parallel cuts the flow rate in half and is difficult to implement properly to insure equal flow for each block. Take a look at the chart below by Bill Adams of Swiftech. In a series plumbed system, the amount of heat transferred to the water after the first waterblock is minimal.

load W . . flow . . . die T . . bp T . . inlet T . outlet T . C/W . . Btus*. . Watts . %eff
45.00 . .2.0/7.57 . . 36.5 . . 27.1 . . 25.00 . . 25.08 . . 0.256 . . 144 . . . 42.2 . . 94
45.01 . .1.5/5.68 . . 36.7 . . 27.3 . . 25.00 . . 25.11 . . 0.260 . . 148 . . . 43.4 . . 96
45.01 . .1.0/3.79 . . 37.2 . . 27.7 . . 25.00 . . 25.17 . . 0.271 . . 153 . . . 44.8 . . 99
45.01 . .0.5/1.89 . . 38.2 . . 28.7 . . 25.00 . . 25.33 . . 0.293 . . 148 . . . 43.4 . . 94

75.02 . .2.0/7.57 . . 45.0 . . 29.4 . . 25.00 . . 25.14 . . 0.267 . . 234 . . . 68.6 . . 91
75.02 . .1.5/5.68 . . 45.4 . . 29.8 . . 25.00 . . 25.18 . . 0.272 . . 243 . . . 71.2 . . 95
75.02 . .1.0/3.79 . . 46.1 . . 30.4 . . 25.00 . . 25.28 . . 0.281 . . 251 . . . 73.6 . . 98
75.02 . .0.5/1.89 . . 47.8 . . 32.0 . . 25.00 . . 25.56 . . 0.304 . . 251 . . . 73.6 . . 98

105.04 .2.0/7.57 . . 53.3 . . 31.6 . . 25.00 . . 25.19 . . 0.269 . . 341 . . . 99.9 . . 95
105.04 .1.5/5.68 . . 53.9 . . 32.1 . . 25.00 . . 25.26 . . 0.275 . . 350 . . . 102.6 . . 98
105.04 .1.0/3.79 . . xxxx . . 33.0 . . 25.00 . . 25.39 . . xxxxx . . 350 . . . 102.6 . . 98
105.04 .0.5/1.89 . . 56.9 . . 35.2 . . 25.00 . . 25.77 . . 0.304 . . 346 . . . 101.4 . . 97

 

[RaiderJ]

I would say do whichever method is easier to implement (most likely series). I don't have any lab data to back up my claim, but I would say that either method will produce sufficient cooling for the processors.

If you do parallel tubing, you have more chances for leaks, extra tees and whatnot also lower water velocity.

 

[Mingon]

I have set it up as follows; pump / reservoir - radiator - cpu 0 - 2nd radiator - 2nd pump / reservoir - CPU 1 - start. This should allow me them sufficiently.

 

[crapito]

parallel works best in theory as the CPUs won't heat each other, however i strongly doubt you'll notice a real-world difference, so go with option #1 as that's far easier/cheaper to setup. the 1st CPU might heat the water a degree or 2 before the second CPU gets it, and IMHO, that's no "real-world difference."

 

[MrThompson]

Having played with both in a PIII dually with a Mag7 and Maze1Cs, I could not get parallel to come close to the performance of series plumbing.