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how much radiator will I need

Discussion in 'Watercooling' started by skulth, 22 Apr 2014.

  1. skulth

    skulth What's a Dremel?

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    Hi everyone

    I have been reading around for quite a while now and think I have the answer but thought I would double check.

    I am looking to build my first custom loop. I have decided I am not going to tip toe around the edge, going straight for the dive.

    So I will soon be building a new PC. Looking at an i7 and 2x780. Which I would like to cool quietly.

    i7 4770k is 84w ( i know this is not overclocked but I'm looking at a base line)
    780ti are 250w each

    So all in I'm looking at a min of roughly 600w.


    My question is how much radiator will I need. I am looking at either

    2x360. http://www.alphacool.com/product_info.php/info/p975_Alphacool-NexXxoS-UT60-Full-Copper-360mm.html

    or 2x480. http://www.alphacool.com/product_info.php/info/p986_Alphacool-NexXxoS-UT60-Full-Copper-480mm.html

    I know the 480 will give me better temperatures for a quite machine. but will I really need that much cooling. Space is not really a concern as I am doing a scratch build. A build log will follow but just doing my design work and some home work.

    Am i right in thinking that a 360 with fan set to 800rpm cool around 500watts with a delta T of around 10-15degrees?
     
  2. Big Elf

    Big Elf Oh no! Not another f----ing elf!

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    Either of those rad configurations will give you more than enough cooling capacity. The more rad space you have the slower (generally) you can run your fans.

    2 x 360 gives you more flexibility with case sizes but 480 rads generally work out a bit cheaper per 120 of rad.

    I suspect you've been reading Koolance's ever optimistic and misleading performance claims. Have a look at Martin's tests

    I recently ran a test system with 2 x 580GTX and an overclocked i7 990X on a Black Ice SR1 480 rad with 4 x AP-14s at 1450rpm and it could easily cope with the Heaven Benchmark.
     
  3. skulth

    skulth What's a Dremel?

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    That's quite interesting. I assuming the difference in performance is due to better modelling of a case based situation. I.e more insulation ect. I always wondered what effect it would have, but halving the cooling capacity it quite substantial.

    Think I am going to base my new case on 2 480's. The extra really can only lower my fan speeds. and have it quieter.
     
  4. Maki role

    Maki role Dale you're on a roll... Lover of bit-tech

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    To be honest, you won't really get it much quieter by going for 480s. I run a 3930k and two Titans on the equivalent of 2x360mm (dual loops though with 480 for the GPUs and 240 for the CPU right now). For me the loudest parts are my pumps, which thankfully are being sorted out pretty soon. I can lower the fans right down and still run with hefty overclocks on all parts. In fact, the GPUs run so cool I'm probably going to remove 120mm from them and give it to the CPU instead, as that could do with some more headroom really. I've got DDC pumps which are whiney buggers, a D5 will be silent and much through that loop with no trouble. Stick some decent fans on those rads and you won't hear them at all, given you should be able to run at low RPMs.

    Still, there's no harm in going 480s at all. I'm mainly mentioning the 360 scenario as it does present more case options. However, if the case you like fits 2x 480mm rads anyway, why not go for it?
     
  5. skulth

    skulth What's a Dremel?

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    does it matter where the radiators sit in the loop?

    It would obviously make a difference to the last component on the loop.

    I was thinking, rad-cpu-rad-gpu-gpu.

    But

    Would doing rad-rad-cpu-gpu-gpu make much difference to the temps in the graphics cards?

    Thinking from a tubing point of view.

    Basically my build looks like

    -2x 360 or 480. Probably alphacool UT60
    -1x Ek D5 pump
    -Monsoon compression fittings - They have reviewed well or Bitspower fittings, again -used a lot and reviewed well, need more research on this.
    -Finally a tube based reservoir.

    Any think wrong here? I have spent year researching and think maybe this time. And now is the time.....
     
  6. Big Elf

    Big Elf Oh no! Not another f----ing elf!

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    Rad placement (providing you have enough) makes little difference to overall temps so it's best to design the tubing to run the shortest distance between components.
     
  7. skulth

    skulth What's a Dremel?

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    Is this due to the system reaching an equilibrium? The blocks only raise the temperature of the water by a degree or 2 at most throughout the system? (due to the relativity high heat capacity of water, a-level physics as quite awhile ago)

    thanks for the help guys. very interesting. solved several of my problem.
     
  8. KayinBlack

    KayinBlack Unrepentant Savage

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    I'm running two different 480s and a 240 in the system I'm building. Got a Swiftech up top for CPU, board and possibly RAM and a Monsta and an xt45 in the bottom for either a trio or quartet (haven't fully decided) of 290x cards. Looking for thermal equilibrium with both setups, running 38mm fans in pull at half voltage for decent static pressure and next to no noise.

    The larger the system, the faster it will get to equilibrium, however you still won't beat ambient-however you can still get close. That's my goal.
     
  9. Nexxo

    Nexxo * Prefab Sprout – The King of Rock 'n' Roll

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    Yup. Also, the difference of air going in the radiator and coming out is only a few degrees.

    Pump should come after the reservoir. The rest of the components can be mixed up. Always go for the shortest path. Avoid a lot of bends. Tubing can go down to 8mm ID before you notice a significant difference in performance; it does not have to be big phat tubing.
     
  10. skulth

    skulth What's a Dremel?

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    in terms of the pump. I going to be using a D5, more than likely a EK variant.

    http://www.watercoolinguk.co.uk/p/EK-Water-Blocks-EK-D5-X-TOP-incl-Vario-Pump-Acetal_42166.html

    At what point would I need a second pump. Seen in places that a loop can lose pressure and becomes less effective. I know this is when you using things like the MoA-3. The monster that it is. With 2x420 on the loop I am coming close to this size though. Will I have enough pump? Never used a D5 so I have no idea what it can do.
     
  11. Nexxo

    Nexxo * Prefab Sprout – The King of Rock 'n' Roll

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    A D5 is quite powerful. Also flow is a bit overrated. I cool 230 Watts on a single BIX with a 69 CFM fan, and flow at 1.7 litres/m. (I know this because I have a flow meter).
     
  12. rts2468

    rts2468 What's a Dremel?

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    You should be fine with 1x480 and 1x240or360. 2x 480 if you can fit would be great, but you would see little difference between the 360 and the 480. I recommend doing a dual loops keep the hotter blocks on the bigger Radiator and a bigger reservoir so you can have more liquid moving through that loop. Also keep the Chipset, Northbridge, Southbridge, and RAM on a different loop because they do not get as hot and do not change and fluctuate in temperature so do not need as big of Radiator.

    Also Intel CPU's are not as Hot as AMD CPU, keep that in mind.
     

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