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Two smaller rads vs one large rad

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a b K Overclocking
August 14, 2010 9:06:06 AM

Just a simple question to you water coolers out there..

Which would be a more efficient loop.. Having one large 3x120 rad at the bottom of your case, or having a 1x120 rad after the CPU waterblock, and then to the GPUs and then a 2x120 at the bottom? Not sure if that makes sense - I'm a little tired.

Cheers.
ace

More about : smaller rads large rad

a b K Overclocking
August 14, 2010 10:26:38 AM

Having the 2 rads means the GPUs are not getting hot water from the CPU but having only one means theres less to go wrong.
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a b K Overclocking
August 14, 2010 5:43:27 PM

Wait, GPUs? What all components do you have under water? If they're strong GPUs, I don't think that a total of 3x120 is enough rad for it to keep temperatures low enough to make it worth having water.

Loop order really doesn't matter, it's something that I've been looking into myself. Generally have your CPU first, as they usually require the most pressure to efficiently cool the CPU. As for the rad position, even if you have them last in the loop or first, water temperatures will be within 3C at any point in the loop, unless you have a very restrictive loop any sharp bends, or 90 degree angles and such).

Under load, the water will reach an equilibrium temperature (basically flattens out), and it will stay that way pretty much no matter where the components are in the loop.
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a b K Overclocking
August 14, 2010 6:00:01 PM

Thank you for your comments. I wasn't really asking about what order, but if one larger rad was better (or worse) than two smaller rads. I also wanted to know if having a small rad right after the CPU and then a 2x120 after the two GTX 260's would be better as the GPU's would be getting cooler water to them.

I have a 720BE @3.6 but this will soon be upgraded to a X6. Should I scrap my whole plan and just have two 3x120 rads? one loop for the CPU and one for the two GPUs?
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a b K Overclocking
August 14, 2010 6:20:59 PM

The CPU will be fine with a triple, but I think you'll need more rad for the GPUs. Each one puts out around 175w or so, so together I think you'll need a bit more rad. I would give it a shot with a triple rad on each loop, but if the temperatures on the GPU aren't kept in check, I'd add another double rad or triple rad, whatever you can get the best price for. :) 

Also, I'd look at www.jab-tech.com for rads and fans. They've got good deals on everything that they have in stock, especially Yate Loon fans. I just ordered a Swiftech triple rad to add to my quad rad, with three Yate-Loon high speed 120mm fans and it cost me $70 with shipping. Just for reference, a quad rad and four of those fans would cost $110, so it's better to get triple rads.
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a b K Overclocking
August 14, 2010 9:59:57 PM

Thanks jedi.
Even in my monster Cosmos S, three 3x120 rads would be pushing it lol. That'd be one at the front, one on the top and one outside at the back - insane! I was looking at maybe getting a Corsair H70 (not the H50) for my new CPU, and then try out a single 3x120 or 3x140 rad for the GPUs. I think one 3x140 should be enough but we'll have to see. As you say, I could always add another rad to the loop.

I'm also lucky enough to have a load of trade accounts set up via my business, so I can buy water components and fans at trade price.. normally 15%-40% cheaper than RRP :) . I have a load of quiet 110CFM scythe fans which were bought for £10 a pop - can't beat that :].
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a b K Overclocking
August 15, 2010 1:06:23 AM

Wow, that's awesome that you can get those parts for cheap!

I think that an H70 would be good for that CPU, as it doesn't use a load of power under load (unlike i7's and such), so that should be fine. As for the GPU loop, I don't know if 3x140 would be enough for two of them, but you can try it. If it doesn't work as well as planned, what would be the next step for you? I know the Cosmos is a big case, but I don't know offhand how much room it would have for rads (I have a custom made benching station, with my rads mounted on top of my desk, so I don't have to worry about space :p  ).

Well, to make that rad work, you'd need Delta fans on it pretty much. And when you read Delta, think the airplane, wrapped up in a 120mm fan. :lol: 

And when you say 3x120 and 3x140, do you mean three separate rads, or one large triple rad?
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a b K Overclocking
August 15, 2010 9:18:10 AM

Well yeah, I'm pretty sure I read that the H50 on the X6 CPU i'm choosing gives around 40C idle and 60C under load when overclocked to 4GHz (going from memory, might be a little higher than that), so the H70 should easily do the job. I'm not even really looking to go to 4.0, but 3.6Ghz would be nice as I'm currently on that with my X3 so it'd be like double the cores, same speed lol.

Anyway yeah.. I've seen quite a few videos now where two 5980's and an i7 are all in one loop with a 3x120 (three fans, one rad) and then also a 2x120. So I'm hoping a single 3x120 (or maybe 3x140) rad would be okay for my 260s. I think it very much depends on the quality of the rad as the H70 is only a 140mm by 140mm rad i believe, but can easily cool the latest i7 six-cores (stock speeds at least).

The Cosmos is huge, and has a perfect spot for a 3x120 rad up at the top. It also has room to have another at the front. So if the H70 does the CPU well, I could really have one 3x120 rad for each GPU! :o 

And no delta fans for me! I buy very high airflow fans (100CFM+) and delta are normally between 100 and 300. I'll just have 6 110CFM fans.. I think that'll do the job on a single rad.

I'll update these forums with pictures and updates once I actually get things sorted.
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a b K Overclocking
August 15, 2010 7:13:44 PM

Sounds awesome! I love watching builds and things coming together.

I was wondering if you saw the most recent system builder marathon here on Tom's where Thomas (one of the editors) decided to put an i7 at 4.3Ghz and an overclocked 5970 (dual GPU) with a Swiftech kit that is meant for only CPU, so it had 700+ watts of heat going into a 2x120 radiator, with a small pump that is NOT meant to handle anything more than just the CPU. Everything inside was cooking, and he blamed it on a "restriction" in the GPU's full cover block (which, by design, are NOT restrictive).

I brought it up to him, and he said that I am wrong, and every other post that says you need a lot of rad for EACH hot component was wrong.

I was kind of turned away from Tom's by that, I didn't come back for a while. Just was odd to me since he always does good work, and always does his homework, except this time.
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a c 324 K Overclocking
August 17, 2010 2:27:24 PM

^Yes, many of us have complained about their 'Watercooled Performance' builds where they really skimp on radiators to cool overclocked i7's and 2-3 SLI rigs. Completley wrong approach.
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a b K Overclocking
August 17, 2010 5:54:25 PM

I know, I just wish that they would listen to us, or at least do some homework.
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a b K Overclocking
August 18, 2010 8:53:52 AM

I've spoken to plenty of builds that spend as much on rads and pumps as they do their CPU and GPUs :o .. several hunred £££. That's the way to do it ;) . Thanks anyway, I'm now looking at getting a H70 for my X6, and two 3x120 rads for my two GPUs :D .

Sorry if this is against any rules, but if you like watching builds Jedi, I have a few build videos here: http://www.youtube.com/user/acer0169
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a b K Overclocking
August 25, 2010 8:17:31 AM

Best answer selected by acer0169.
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