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Seeking opinions: Water-cooling 8800GTS x2 and AMD x2

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April 2, 2008 7:31:06 PM

Hello, techies!

This forum and its users is a wealth of knowledge, so I figured this place is the best arena to pose this question: How would you implement water-cooling for two 8800GTS video cards and two AMD processors?

I am looking to build a new multipurpose system based on the 860a SLi motherboard, and it seems just about everyone has a different opinion on how to accomplish this. Dual water cooling systems? A single system with extra powerful pump and radiator? Someone even suggested an inert fluid case, although I have only seen one of these and it was rather problematic. Any advice, no matter how trivial, is appreciated!
April 2, 2008 11:33:11 PM

There's actually a pretty good discussion going in now on overclock.net on whether dual loops really offer any advantage over a single loop. Here are some things that most agree on:

1. Flow rate is optimal between 1-1.5 GPM. Whether you do that with multiple pumps or one doesn't matter. Greater than that doesn't offer any appreciable decrease in cooling.

2. As a rule of thumb, if you think of each 120mm fan on a rad as a "section", plan for 1.5 sections per block and .5 sections for chipset blocks. (obviously, rads and fans vary).

Taken together you'd need a pump cable of moving your fluid at 1-1.5 GPM and 6 sections. That could be three 220s, two 360s, a 480 and a 220, etc.

You can estimate flow rate under the single/dual loop scenerios using "Martin's Flow Rate Estimator:
http://www.martinsliquidlab.com/MartinsFlowRateEstimato...

You can try it with one large pump, two pumps, single loop, or dual loop. As long as the flow is over 1 GPM then the choice between single or dual is mostly personal convenience.
April 3, 2008 6:34:45 AM

Personally, I recommend 2 loops. 1 loop for cpu's, and 1 loop for video cards. Having all of them in one loop, unless you have dual pumps, and dual rads in the same loop, won't be a good idea, as it will overload the capacity of the radiator to cool efficiently. Not even a single Thermochill PA 120.3 can handle that much heat when at full load. With the risk involved of cooling 2 cpu's and/or 2 video cards in the same loop, let alone in dual loops, you run a great risk if a pump fails.

You should try to keep flow rates above 1.5 gpm, that way you can always go with a more restrictive block or radiator, and still be in the safe zone. Martin even made this same recommendation in the same web page TonyL222 mentioned in his post.

My recommendation also includes that you should spare no expense in purchasing your components. If you are going to spend that much on cpu's and gpu's then you should take that much care in cooling them properly. I also encourage you to read up incessantly in preparation of purchasing your components. Sometimes, the best system isn't always the most expensive.
April 3, 2008 11:13:06 AM

Groveling_Wyrm said:

You should try to keep flow rates above 1.5 gpm, that way you can always go with a more restrictive block or radiator, and still be in the safe zone. Martin even made this same recommendation in the same web page TonyL222 mentioned in his post.


Yep, having "spare" capacity just for any new additions is good idea. 1 GPM is the absolute bottom, but 1.5 GPM is a better target. He is definitely going to need multiple rads as even a single 480 isn't enough. One of the advantages of a single loop with dual pumps is a built in backup in case of a single pump failure.

I would lean toward dual 360 rads (or even dual 480s for spare capacity) just for symmetry. I would also get two pumps. Forget the debate over single vs dual loops. With the equipment you'll need, you'll have the flexibility to go either way. You could try them in a single loop then later dual loops (or vice versa) and see which gives you better results. If you use Ts then you won't have to worry about dual reservoirs.
!