Split Loop Question

[Stevereno]

Does it make sense to run the northbridge, southbridge and MOSFET cooling in parallel to the CPU GPU loop as follows:

.................pump
.....................|
....................V
............360 x 120 rad
....................Y
...............|...........|
.............cpu......NB
.............gpu......SB
.............gpu..MOSFET
................|..........|
.....................Y
................... res

All pros and cons welcome - all swiftech blocks (except MOSFET) 1/2 inch ID tubing, 317 GPH Pump. Black Ice Pro X-core 360 x120 rad.

Or maybe it would be better to split it with CPU NB SB MOSFET on one side and the 2 GPU on the other.

 

[nonlnear]

Are your NB and SB blocks the same model? I'm assuming they are.

The thing you want to focus on is balamce. The problem with a split loop is that water will take the path of least resistance. That's bad because the blocks with the most resistance are usually the ones with the biggest heat loads to dissipate. So to avoid wasting the majority of your flow on the least important part of the loop (the NB, SB and mosfets), you need to balance things out.

If you really want to split the loop, here's what I'd do:

. pump
. . . |
. . rad
. . . |
. . CPU
. . . |
. . . Y
| . . . . . . . . |
GPU . . . GPU
| . . . . . . . . |
NB . . . . . SB
. . . . Y
. . . . res

Aside from balancing the flow restriction, this has the added benefit of not having the usual tight radius turn between the GPUs. On most boards, all the turns will have a fairly large radius. What motherboard are you building on?

If your mobo takes two MOSFET blocks, I'd put one in each lobe of the split part. (Once again, what mobo are you using?) If it only takes one, there is no good place to put the MOSFET block in that loop. The "least bad" place is after the two lobes merge - before the reservoir. (Personally I'd dump the MOSFET block(s) for passive sinks anyways, but that's not helpful to your project.)

 

[Stevereno]

The Motherboard is a Asus A8N32-SLI Deluxe. It curently has 2 MOSFET passive coolers, one of which is on a heatpipe with the NB and SB

 

[Arcygenical]

Why are you watercooling the MOSFETs with water?

 

[nonlnear]

Unless you really really really want to mount the board in a compartment with absolutely NO airflow, you're probably better off just leaving the NB, SB, and MOSFETs with the heatpipe unit on them. If there is any airflow in the case, they should be fine.

If you really want water for the MOSFETs, and NB/SB, then I'd put a waterblock on each of the sets of MOSFETs, and put one of each of these on each of the split lobes after the NB/SB blocks.

 

[Stevereno]

Thanks for all the feedback. Here's the beast.

 

[Stevereno]

Here's my Project Page Link

Water Cooled Lian Li PC-343B Project

To answer the previous question by Arcygenical. The MOSFETs are being water cooled to eliminate a need to air cool them. Plus the heatsink for one secton is one piece and covers MOSFET SB and NB. I could leave that there but if I'm going to be using water I'm going all the way.

Page 3 of the website covers the water flow based on a modified version of nonlnear's suggestion. Thanks again!

 

[calvin_q]

If you go with a 3 barb block like the RBX or Whitewater you can eliminate the Y piece by the cpu. Plus there are res designs with dual return ports so that Y could be eliminated as well. Just a suggestion to reduce overall # connections.

 

[Stevereno]

Thanks calvin_q. Thats a good idea but I have the block for the cpu and a reservoir. I could connect the res 3rd port on the return. I will just have to see how it lays out. I was planning to use a temp sensor in the 3rd port of the res. I'll just have to see it all plumbed up first.