2nd radiator between CPU and GPU?

em00guy · Aug 18, 2004

In an effort to prevent warm water from washing over the GPU I thought it might serve to place a small 2nd radiator in my loop between the CPU and the GPU. This way the water from the CPU is cooled abit before it reaches the GPU. Would this pose any concerns?

THE_ODD_ONE · Aug 18, 2004

As long as your pump can handle the extra load.
and you can handle the extra fan noise, than I say go for it.

I have seen some people say that it really helped there vid card alot.

and of course others say that the cpu relly does not heat the water enough to NOT cool the gpu very well.

greenman100 · Aug 18, 2004

no concerns, but it shows you will benefit from an article to be posted on the frontpage. (overclockers.com)

in short, order of components makes less than a 1C difference. So adding the second radiator will help, but it doesn't matter if it's before ot after the GPU.

em00guy · Aug 18, 2004

greenman100 said:
no concerns, but it shows you will benefit from an article to be posted on the frontpage. (overclockers.com)

in short, order of components makes less than a 1C difference. So adding the second radiator will help, but it doesn't matter if it's before ot after the GPU.

Ahh, i forget the front page exists sometimes i'll check it out. It will actually be my third rad. the first 2 wil will be serieis 2-342's, But i didn't want you guys to be jealous of my l337itude.

nikhsub1 · Aug 18, 2004

em00guy said:
Ahh, i forget the front page exists sometimes i'll check it out. It will actually be my third rad. the first 2 wil will be serieis 2-342's, But i didn't want you guys to be jealous of my l337itude.

If that is the case, two 2-342's, then a 3rd rad is totally and utterly useless and can only do more harm than good.

greenman100 · Aug 18, 2004

em00guy said:
Ahh, i forget the front page exists sometimes i'll check it out. It will actually be my third rad. the first 2 wil will be serieis 2-342's, But i didn't want you guys to be jealous of my l337itude.

it's not there yet, it'll be there tomorrow

another vote for way more than enough raddage

even my single 2-342 brings about 100w to 5C above ambient with a near silent blower.

em00guy · Aug 18, 2004

We'll was under the impression that a rad in between the procs would help because it is in a different location in the loop. Guess i'll read that article manana.

greenman100 · Aug 18, 2004

em00guy said:
We'll was under the impression that a rad in between the procs would help because it is in a different location in the loop. Guess i'll read that article manana.

replace "pump" with "GPU" and you'll get the idea

article said:
Myth: Order of components makes a significant impact on temps. (e.g. radiator must be before CPU)
Reality: Order of components makes a difference of less than .5C in most watercooling systems. The physics:

pump---->radiator---->CPU---->pump
pump---->CPU---->radiator---->pump

There is only one difference, and that is the position of the pump in the loop, be ir before it after the CPU.

Assuming the pump dumps about 50w of heat into the water, and flow rate is 1GPM (very reasonable):

Water has a thermal capacity of 4186J/Kg-C at 22C, and a density of about 1g/mL

With a flowrate of 1GPM, that’s ~3.75LitersPM.

3.75LPM/60 seconds= 0.0625Liters or Kilograms through the waterblocks per second.

4186*0.0625=261.625W/C

So that's 1C warmer for every 261W

But only 50 watts of heat are present, so: 50/261.625=.19C

So, there is a .19C difference in water temperature between the inlet and outlet of the pump. This does not mean the water is only .19C warmer than air, that is an entirely different calculation.

And that’s with 50 watts. If you’re running a smaller pump, like the D4, you're looking at 15w or so.

So, do what allows for the simplest tubing runs, tubing length/kinking will have a greater impact on temps.

em00guy · Aug 18, 2004

Thats rather profound, Does this mean that we have been over emphisising heat transfer
from pumps. So my velocity t1 will barely effect water temp, especially since it's behind 2 2-342's

greenman100 · Aug 18, 2004

hm.

maybe my article WON'T work as planned.

So, there is a .19C difference in water temperature between the inlet and outlet of the pump. This does not mean the water is only .19C warmer than air, that is an entirely different calculation.

em00guy · Aug 18, 2004

greenman100 said:
hm.

maybe my article WON'T work as planned.

Well ok, forget about the "behind 2-342's" part otherwise do I have the jist of it or is my n00balicious hanging out?

greenman100 · Aug 18, 2004

haha.

ok.... there are two factors to consider here

the delta T of water to air, and the delta T across the pump or other heat source.

the delta T of the water to air is dependent on radiator efficency

the delta T across the pump is dependent on the flowrate and cooling fluid

starting to make sense now?

em00guy · Aug 18, 2004

ooooohhhhhhhh I get it (I think). I didn't read your post thouroghly. So better flow means less heat tranfered to the water. So if was moving 2Gpm Then:

7.5 lpm / 60 s = .125 lps

4186 J * .125 lps = 523.25W/C

So for the temp rises 1 deg for every 523.25 watts of heat

or in the case of a 50w pump 50/523.25 = .099 C

and my 98 W t1 98/523.25 = .18 C.

Let me know if we are on the same page because it's getting late for me and I'm still @ work so i'm not focusing

greenman100 · Aug 18, 2004

the same amount of heat is transferred, but there is more water to transfer it to, if that makes sense....kind of like replacing a fan with a bigger fan.

what matters is your understand of the difference between overall water temp and the difference in water temp before and after the pump.

2nd radiator between CPU and GPU?

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