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PostPosted: Mon Oct 29, 2007 8:54 am 
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Location: West Yorkshire, UK
For a 1.4v x2 4200 & 7800GT, 123w heatload + pump heatdump... 141w total maximum heatload (assuming an 18w DDC for the pump, and assuming that that pump dumps 100% of it's heat into the water, which it doesn't... so probably about 130w altogether).


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PostPosted: Wed Nov 07, 2007 5:15 am 
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You are out of road my friends! I red on OC an article I can't find about an oil like water (same viscosity, same weight, same thermal conductivity) but without electrical conductivity and no risk of algae. I sent a mail to Joe Citarella asking the right link, as he answers me I post the link. Bye bye.


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PostPosted: Wed Nov 07, 2007 5:25 am 
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As in the 3M inert coolant that costs an absolute fortune - Flourinert? No-one uses it as it costs a ridiculous amount of money - $200USD per gallon. Old news I'm afraid... 2002.

http://www.overclockers.com/tips1098/index02.asp

AFAIK, there is no liquid that has the same specific heat and thermal conductivity as distilled water.


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PostPosted: Wed Nov 07, 2007 6:01 am 
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It's not what I red. Probably it's before 2002... It was an oil not so expensive. Maybe I'm wrong but that's what I remember.


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PostPosted: Wed Nov 07, 2007 6:13 am 
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Cooking Oil is used in submersion cooling, but still doesn't outperform water (by a long shot)...

If that ain't it, find the link, as you've seen an article that the rest of the world has missed.


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PostPosted: Wed Nov 07, 2007 6:58 am 
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Are you thinking of Opticool or Luminol TRi?

http://www.ocforums.com/showthread.php?t=494311 has an explanation of the pitfalls and links to other info on the subject. Another decent read: http://www.hardforum.com/showthread.php?t=851060.

Neither can replace water, but I am trying to get ahold of some Luminol TRi for my watercooled PSU experiment.


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PostPosted: Mon Nov 19, 2007 3:19 pm 
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Location: UK
Marci, I'm still not totally clear on how to calculate what kind of rad is required for a certain load. Perhaps you can help?

Say I want to cool a QX6700 (130W) and 8800 Ultra (175W). Maybe a NB as well, what is reasonable for a 680i chipset? Recycle my current Eheim 1080 pump. Say 25C room temperature (optimistic in summer, but for the sake of argument).

A few things are not clear. For example, the tests at http://www.thermochill.com/PATesting/index.php assume a 10C water/ambient differential. Realistically, how hot can the water get to maintain reasonable component temperatures? Say 55C max for the CPU, 80C for the GPU and not-on-fire for the NB. It must depend on the waterblocks, thermal interface etc (lapped my CPU, btw, took 8C off the temps and the Arctic Silver isn't even burnt in fully yet).

Of course the goal is to have the smallest radiator with quietest fans possible. Nexus 120mm at 7V (or even 5V) would be ideal. Is it possible to get an idea of temps with say my heatercore vs a PA120.3? Is there a way to calculate the temperature of the air after it has passed through the radiator (in case I wanted to suck air through the rad and into the case, assuming it was cool enough)?

For me this has always been the biggest issue with water cooling - it's very hard to tell how well components are likely to perform unless you simply go for the biggest, highest performing parts.

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PostPosted: Tue Nov 20, 2007 2:42 am 
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It gets tricky using my method for comparison to other equipment from other manufacturers, simply because very few provide the data. For instance, there isn't the necessary data for the specific Heatercore radiators to allow me to compare a theoretical PA based system vs a theoretical Heatercore based system.

Have a look here:
http://www.over-clock.co.uk/ivb/index.p ... opic=20277

Reason why I don't work in CPU / GPU temps and instead work in coolant temps is that no-one has done consistent testing of all CPU and GPU blocks on a single testrig, and even if they had, a single testrig can't represent differing Die sizes / Heatfluxes. You'd have to have several testrigs, one producing data that's useable for quadcore, the other producing data for dualcore, doubled up - you'd need one of each for intel, one of each for AMD, as their die sizes differ and thus so does the heatflux etc. This means c/w figures from different sources can't be used simultaneously in one equation. C/W figures calculated for a waterblock using a dualcore processor can't be used to predict performance of a quadcore processor... and vice versa... and data derived from an AMD cpu as a heatsource can't be used for an Intel CPU... etc etc... so you have to find someone who has tested the same block with the right type of CPU. It all gets tricky. This means that really it's much easier to base it off known radiator thermal dissipation.

There are some brands where one can predict performance - eg: Swiftech. If you have a loop consisting of all Swiftech blocks then their C/W data tends to be useable, as long as you have a processor matching the characteristics of their c/w charts (ie: they have a chart for singledie cpus, and one for dual die cpus - make sure you use the right charts).

EG: To work out CPU temps...
ambient + ([radiator c/w]*[total_loop_heatload]) + ([cpu_wb_c/w]*[cpu_heatload])

To work out GPU temps...
ambient + ([radiator c/w]*[total_loop_heatload]) + ([gpu_wb_c/w]*[gpu_heatload])

ambient = temp at radiator air inlet.

The bolded section is this: ambient + differential.
radiatorc/w * total loop heatload = differential.

This calc usually done at full load. You can use 50w to approximate an idle graphics card if you want CPU temps with GPU idle... and the figures are available for CPU Idle Load if you want CPU idle with GPU at load, or indeed just predicted temps for both at idle. (Refer to Intel Whitepapers for their CPUs for their idle loads).

Armed with that info, you can now find out what CPU and GPU temps would be produced and deduce what the "ideal" max tolerable differential would be.

Bear in mind, all stated power consumption / heatloads out there tend to be OVER calculated - ie: they are above the actual real-life figures. If you calculate as above for your setup, you should always have some headroom as a result.


Calcing the temp of air at exit of the rad... again, tricky. Yes it COULD be calculated as a c/w figure could be produced... but someone would have to sit and produce the data to get that c/w figure, and it would have to be done for EVERY fan, with each fan being tested across a wide range of heatload and flowrate - a VERY longwinded task. I'll state now tho, everyone I know, myself included, all suck air into the case thru the rad - ie: mount the rad on chassis air inlets / use it as an air inlet, which means it's heated air is dumped into the chassis and exhausted out the back. I've never had any issues with case temps being over the odds... nor has anyone else I know who runs a similar config.


Max water temps - I personally like to keep 40 deg C as the very highest... much above this can cause tubing to soften etc, which runs the risk of the tubing collapsing, and in setups where clamps aren't used (eg: 7/16 ID over 1/2" barbs) could result in tubing sliding off the fittings.


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PostPosted: Thu Nov 22, 2007 12:08 pm 
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Joined: Mon Nov 05, 2007 7:44 am
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Location: Italy
Finally I found the discussion "the rest of the world has missed": http://overclockers.com/tips653/
However I didn't find all the infos I remember I red; anyway it is not a submersion experiment but a "normal" liquid cooling with a radiator. It's surely this (this is where I found the link: http://www.hwupgrade.it/news/cpu/recens ... _4621.html)

P.S.: probably I red the said infos reading the last comment on HWUpgrade (sorry they are in italian): probably because of this I remember to have red about the cooling capabilities etc. of this oil.


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PostPosted: Thu Nov 22, 2007 5:30 pm 
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Location: UK
Marci, I wrote a long reply but it doesn't seem to have appeared on the forum.

Long story short, with a PA120.2 and 2xNexus 7V my CPU should stay under 60C, assuming it hits the full 130W and my total system load is about 315W (CPU 130W, GPU 175W, 10W for pump/case). Decided NB will be okay on air.

One issue I am having is finding reliable info on GPU waterblocks. 0.085c/w is the rated efficiency for the Apogee GTX, but for some reason they don't give figures for the Stealth Full Coverage GPU block. DangerDen don't either. They quote 0.045c/w for their GPU only block, which seems odd as their CPU block (which is doing pretty much the same job) is much worse...

Maybe their test CPU was a Core 2 with a concave heatspreader. I lapped mine and it took 10C off.

I made a spreadsheet to calculate temps and compare rad/fan combinations. A PA120.3 would be ideal since it costs only a little more but would give some headroom. There is no good way to mount it on the P182 without massive modding though, while the PA120.2's barbs line up with the P182's grommets and PCI slots perfectly.

Maybe put an extra 120mm rad in the front as well? Wouldn't do flow rate much good.

Something else interesting I found: http://www.turborocco.com/gallery/v/new ... 7.jpg.html

How does the res not overflow?

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PostPosted: Mon Nov 26, 2007 8:51 am 
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Because the system isn't open anywhere else...

Take a drinking straw. Dip it into a pint glass full of water, put your finger over the end, lift it up. Water stays in the straw. Remove your finger, water falls out. Exactly the same thing going on.

You'll never find reliable info for GPU blocks I'm afraid... unless ATI or nVidia make a GPU TTV similar to Intel's CPU TTV...


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PostPosted: Mon Nov 26, 2007 1:36 pm 
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Ah yes, vacuum. My brain really isn't working too well these days :oops:

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