How to calculate the amount of Rad you need?

keikeimok

keikeimok

keikeimok

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Hiya, I saw from the web saying how much Watt of system needs XX rad to handle, is there any equations to that? Are they talking about the wattage of the GPU or something else?

say how much Wattage could a single 120 rad could handle? :confused:
 
keikeimok said:
say how much Wattage could a single 120 rad could handle? :confused:
Click to expand...

it would depend on:

- thickness of rad
- fin density
- water pass throughs
- the fan
- etc etc


A rule of thumb I use is that each component needs one 120mmx60mm "piece" + one extra

So a cpu and gpu would need a 360mm rad (120+120+120) 60mm thick

Or a crossfire/SLI system would need 480mm rad 60mm thick

If you go with slim rads (30mm) then you need to double the amount of rad area to account for the loss of thickness. Similarly if you go for those Monsta rads that are 85mm thick or something then you can get away with less area because of the increased thickness.

What are you planning to run on these rads?
 
Uncle Petey said:
What if you had a 30mm rad with double the FPI of a 60mm?
Click to expand...

Okay, im going to make up some maths:


Panyan Radiator Theorem (PRT)

PRT = Rad Length (mm) x Rad Thickness (mm) x (FinsPerCentimetre (F/cm) /10)

[PRT] = mm x mm x (F/mm) = [Fmm] -> FinMillimetres

(Convert FinsPerInch to FinsPerCentimetre)

For example:

240mm x 60mm x ((2F/cm)/10) = 2,880 Fmm

240mm x 30mm x ((2F/cm)/10) = 1,440 Fmm

480mm x 30mm x ((4F/cm)/10) = 5,760 Fmm

480mm x 60mm x ((4F/cm)/10) = 11,520 Fmm

480mm x 80mm x ((2F/cm)/10) = 7,680 Fmm

So by using my new theorem you can work out an exact value for a radiator and compare different radiators.

Real world example:
EK CoolStream RAD XTX (360)

http://www.overclockers.co.uk/showproduct.php?prodid=WC-161-EK&groupid=962&catid=1523

11 FPI -> 4.3 FPcm

360mm x 60mm x ((4.3F/cm)/10) = 9,288 Fmm
Click to expand...

Phobya XTREME Nova 1080

5 FPI -> 1.96 FPcm

1080mm x 45mm x ((1.96F/cm)/10) = 9,526 Fmm

(this rad is basically 3x 360mm rads stuck together, but because the thickness is only 45mm and the lower FPI means it doesnt score as well as 3x 360mm)
Click to expand...


Disclaimer: Use at your own risk. I take no responsibility if this Theorem gives you a false impression of radiator performance. :p
 
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WOW! Thanks for your input. Really learned a lot.
I am having 2 setup atm. I think neither one is qualified as adequate.

One is CPU(4770k), 2 X 7990, 1 360 and 1` 120 EK think Rad.
The other is CPU (FX8320), 6990 X 6970, 1 360 XSPC thin rad 1 120 EK thin rad.

Things are, under heavy mining, the one with the thin rads never go beyond 69 while if only use 3 GPU from the 7990, it will go beyond 73.

I was thinking both are using 3 GPU, but still the thin rads seems doing a better job than the thick one.

As you know both CPUs are more or less idle while mining......
 
It's easier than that - martin's liquid lab tests radiators thoroughly. You can look up the C/W value for a given radiator & fan (I tend to remember 0.06C/W for a 120mm radiator with normal fans).

Add up the wattage of whatever you're cooling (also found online), multiply by the C/W value for the radiator setup you're using, and bang - you have water temp over ambient.
 
All that is bunkum really for computer water cooling, all you need to know is thin hi fpi rads need faster louder fans than thick low fpi rads. And that there are a lot of variables to take into account, but the performances of radiators in general is surprisingly close.

Check out this roundup from Martin's Liquid Labs:

With that I would say generally the thermal performance differences are relatively small, but there are some generalities:

  • Copper Tubes are better than Brass Tubes
  • Thicker radiators generally can be tuned for a broader range of RPMs than thinner
  • Thicker radiators can perform better than thinner radiators, but the difference is not more than 5-10% typically
  • Flat tubed radiators perform better than round tubed radiators
  • Slim 30mm radiators can be tuned to perform extremely well in specific areas, but generally that means loosing more in the opposite area (ie a high speed tuned slim radiator won’t perform well at slow speeds)
  • Build quality does vary and here you do get what you pay for.
  • In performance, you don’t get what you pay for.
Click to expand...
 
Another important factor is how hot/cool do you mind/want the components to be, and how much noise is enough/too much? as the cooling loop required will change drastically depending on that.

I.E I have a pair of Thermochill rads in my system, a PA120.3 and a PA160.1, that's the equivalent of about 6-7 standard 120mm rads but the cooling wattage will vary greatly depending on the fans used. If I was to stick 500RPM slipstreams on everything it would be inaudible unless you put your ear next to the fans but it wouldn't be able to keep my 4.5GHz i7 3820 and GTX680 much cooler than air, however if I was to stick 1850RPM GT's on everything then I could probably swap to a 3930K and SLi Titans while getting better temps (but it would be loud).
 
ubersonic said:
Another important factor is how hot/cool do you mind/want the components to be, and how much noise is enough/too much? as the cooling loop required will change drastically depending on that.

I.E I have a pair of Thermochill rads in my system, a PA120.3 and a PA160.1, that's the equivalent of about 6-7 standard 120mm rads but the cooling wattage will vary greatly depending on the fans used. If I was to stick 500RPM slipstreams on everything it would be inaudible unless you put your ear next to the fans but it wouldn't be able to keep my 4.5GHz i7 3820 and GTX680 much cooler than air, however if I was to stick 1850RPM GT's on everything then I could probably swap to a 3930K and SLi Titans while getting better temps (but it would be loud).
Click to expand...

I see. Cheers!
 
Monsta 360. 10FPI I believe. I just rounded it 4fpcm.

I'm perfectly happy to accept that I might have got it wrong as even with a calculator and written instructions, I'm still **** at maths :D
 
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