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How much rad is needed for an i7??

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stang8118

Member
Joined
May 28, 2004
Ok I am really thinking of going water cooling on my i7 build at the end of this month. I am going with the i7 860. Now I am not looking to go nuts where I will be OC'ing more than 1ghz, looking at water cooling for mainly noise reduction with a mild overclock.

I am going to be either using a Sugo SG02 case, or I am thinking of an Antec P180 mATX case. Obviously space is going to be at a premium, so I don't wanna get more than I really need.

The only thing on the loop is going to be the pump, cpu, and rad. Can I get away with a single 80mm rad? Do you think I'll need a 120mm rad, or possibly a dual 80mm fan rad setup? Thanks~!
 
Can I give you a prep on wattage generated vs wattage removed?
A short answer is a good 120x2 with medium speed quality fans is enough. A 1 Ghz bump, hmm it might be possible depending on your chip, cooling system, motherbaord and your knowledge in overclocking.
A place you should bookmark is:
http://www.skinneelabs.com/

DT Temps

A delta measurement is used in many engineering terms in many disciplines. I guess it means the difference between two of the same thing.

In water-cooling it's simply the difference between the ambient air temps and the water temp on the outgoing side of the rad. Room temps vs. water temps. A better rad setup cools better. Load meaning heat created. Stable meaning the load has been running long enough so the loop is stabilized, heat is made; it is removed and run long enuff for the water temps to get to the max under a load.

If your ambients are 60C and your water exiting the rad is 65C, you got a 5C DT. And it’s important you understand this simple concept. You need xx cooling for xx heat load for a resultant xx DT. Its how you decide what size radiators you need as a minimum for the loop to perform better than air, and what’s needed for really superior max over clocks.

So for example, in a water cooled loop you generate 200 watts of heat. Your block pulls heat into the water; the heat is dissipated into the air by the rad/fans. Skinnee and Martin came up with a great chart for rad test results. Make xx heat, run xx fans with xx radiator brand and size, your DT is xx.

The efficiency of the rad determines the residual heat in the water as it circulates. A rad cannot remove ALL the heat. Heck if that was true, running a rad with no heat load would cause the water to go all the way down to below freezing theoretically. A great Delta T is under 5C, meaning you got a big rad for your heat load. Medium DT is 10C, and 15C is getting bad. CPUs need lower DT than a GPU loop.

Ultimately lucky folks with cooler temps year round can go with lesser rads. People with high ambient might need bigger rads for the same final core temp on a CPU that someone in Norway vs. Samoa can get.

Hope that helps, it’s a simple explanation, I'm not a Thermodynamic engineer.
 
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sorry to burst your bubble (assuming your in one) but a none of the rad sizes you listed will do. minimum is a dual 120mm sized rad. a triple would be better but since your not going with crazy overclocks then a double should be fine.

you can hang the rad off the back of the case externally with various brackets like the swiftech rad box or koolance one, both linked below.

Swiftech radbox

Koolance Rad box.
 
I have 2 kids lol... there isn't much bubble left to burst :D

I wasn't aware that I would need such a large radiator for just the CPU. I remember using a single 120mm size rad for my old P4 Prescott and it kept the temps perfectly fine. I know that was a thermal plant with all the heat it was known to put out. Then again I have been out of the watercooling game for quite some time now.

Can you recommend me a good block, rad, and pump? I would like to keep the pump as small physically as possible since it'll be kept internal most likely. Also is Tygon still the preferred tubing of choice? 1/2" diameter too right?
 
Awesome thanks Spawn. This will keep me busy the next few weeks trying to figure this all out :D

I might just say screw it and get a much larger case. I just got a feeling that this new build is gonna pull me right back into the OC'ing/Modding game lol.
 
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