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484 posts

Ultimate Geek

#62558 9-Jun-2010 19:44
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Hey everyone,

I built an i7 920 based computer around the middle of last year, after having spent quite a while pining over how I would construct it. I had looked at building two separate systems, one as a HTPC/media server and another that would serve as a work computer. After looking at the price of building two separate computers I ended up deciding I could easily combine both roles into a single computer, and use money saved by avoding duplications (such as PSUs, mobos etc) into purchasing a single computer that did more than the two combined.

We have an entertainment cabinet sized for an old CRT TV, so with our 32" LCD HDTV I decided it would be possible to place the computer behind, but after a few months I decided the airflow was not optimal, resulting in a computer that was running a bit hot and a bit noisy for our liking (never mind the fact the lounge room gets pretty hot with the fire on).

Luckily, our lounge room is directly above our garage with 1970s wooden floors separating the two and a loft hanging from the garage ceiling. I drilled a hole up through the floor flush with the wall (drilling up into the wall cavity wasn't an option and the entertainment unit hides it perfectly) and then pushed up an HDMI cable and USB extender (for a wireless keyboard and mouse).

The system works perfectly for my needs, although I must admit playing games on a TV isn't as easy as I expected it would, but the picture looks amazing (even with just a Radeon HD 4770). But having done that I found I simply had too much time on my hands... So I decided on a new project - water cooling!

Now I could have gone for a relatively simple build and grabbed an all in one kit, but I decided I'd try and do something a little more creative... A few months later and I'm one marginally leaky connector away from what what I would proudly say is an insane cooling system.

Inside the computer I have the only actually computer cooling part of the entire rig: a Zalman water block, because its on top of what was worth a couple of thousand dollars, I decided I'd go legit there. But that's where standard finishes!

The water is pushed into the waterblock by an aquaflow pond pump, immersed in a resevoir furnished from a Klip it container. Funny story about the pond pump, I got it from the switched on gardener not long before it got visited by the boys in blue.

After having passed through a reducer as the waterblock is 10mm and the pump is 19mm. Once it's been through the water block, it is then passes through another reducer that brings it back up to 19mm for it's trip to the radiator.... 5 metres away.

The radiator is actually a Ford Falcon heater core, which forms the back end of the cooling unit: a mdf box that contains the radiator at one end and 30cm desk fan at the other. It is about 30cmx 30cm x30xm. The cooling unit has enough space for another heater core, should I ever decide to put another one in, and the fan pulls the air through the heater core and vents it out under the house.

As I said, I'm a single slightly drippy connector away from putting the system into serious water tightness testing and then tests to see how well it cools the CPU. As far as powering the system: I'm going to put the pump on my UPS and depending on how well the radiator cools the system without the fan operating, I intend to put the fan on a non UPS circuit. In any event there is roughly 6l of water in it, and about 20 minutes of run time on batteries, so the temperatures shouldn't rise that much in that time period.

Anyway, I thought I'd share my project with the team here - I have photos if anyone would like to see them:

CAD drawing:

Cooling unit:

Heater core:


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219 posts

Master Geek

  #340130 10-Jun-2010 11:35
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Oh wow. That's awesome.
What kind of temps do you get now that you run water? 

Desktop: i7 920, GTX 275, asus P6T, antec 1200, 6gb ram, 1tb spinpoint f1, 1tb spinpoint f3, Logitech Z2300, Zero DAC, Shure SRH440
Laptop: Toshiba satellite, T5300, Go 7300
Home Theatre: 32" loewe CRT, Harmon kardon amp, dvd player, image 418 speakers, rega planar 25 turntable :)


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780 posts

Ultimate Geek
Inactive user

  #340132 10-Jun-2010 11:40
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Ha, nice one. how much power does this use?


484 posts

Ultimate Geek

  #340142 10-Jun-2010 11:56
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I'm actually still a step short of put the system into testing - I have a minuscule drop in one of 10mm -> 19mm connectors and, on further investigation, found that I have the water going through the waterblock in the wrong direction!

I'm not sure how hot the system will run. My i7's OC'd to 3.78Ghz and running folding@home 24/7, but generally sits between 60 and 70 degs depending on ambient temperatures. One of the benefits of having it in the garage! There seems to be a heat gradient in the garage so having the cooling unit lower down should give it access to cooler air.

Once I have the system running I'll probably keep it at the same clocks, but I'll be able to remove or turn down some of the fans whirring and also look at fashioning a front grill for hiding the computer behind...

The pump itself seems to be only using 7W at the plug, so not quite sure what's going on there, I expected more. Not sure about the deskfan, but its rated @ 50W on 3, probably won't run it on more than 1 or 2.

Overall, the system draw of the i7, a webserver, router and ADSL modem is around 320W at the plug, including the loss attributed to running it through the UPS.

7564 posts

Uber Geek

  #340149 10-Jun-2010 12:22
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Are you able to vary the flow rate via the pump, or does it run at a standard speed?

What is the pump flow rate and the total amount of coolant ( ie how fast is the recycle rate)

The radiator you are using is designed to radiate a *huge* amount of heat, ( large numbers of kilowatts), you may be able to run it quite happily without the fan as your heat source is probably a few orders of magnitude smaller than a trusty Falcon. might save you a few $$$ on the power bill


484 posts

Ultimate Geek

  #340157 10-Jun-2010 12:43
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It's a standard speed pump, I'm not sure on its flow rate, although with the amount of head in the system (over a metre) it's not that high. I also think the drop to 10mm for the water block takes its toll. Push comes to shove if the temps are too high in testing I'll just drop in a second pump to compensate for the drop in pressure due to the head of the system.

The total amount of coolant (including reservoir) is around the 6l mark; which means it'll take the water block over 3 and a half minutes to raise the temperature of it by a single degree when running passively.

I hear ya when you mention that the heater core is good to drop a lot of heat, but it generally does that at a much higher heat differential, I really want my loop to be as close to ambient as possible. Either way; we'll find out in testing once I've fixed up the last few issues :)

439 posts

Ultimate Geek

  #340784 11-Jun-2010 20:35
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could you please post the pics link and how much did you spent, nice work


439 posts

Ultimate Geek

  #340787 11-Jun-2010 20:36
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could you please post the pics link and how much did you spent, nice work



484 posts

Ultimate Geek

  #349721 10-Jul-2010 10:33
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Haven't had a chance to follow up the previous project over the past month... But looking to get some work done on it this weekend....

Regarding the cost a rough estimate as follows,
$75 Zalman heatsink,
$50 Pump
$25 Desk Fan
$40 20mm and 10mm Tubing
$20 Fittings
$10 Expanding foam

MDF was lying around so didn't include that, also need to get some sealant to put around one of the seeping components.

Also need to swap the 10mm tubes around as the water flow into waterblock is currently running backwards.


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Uber Geek

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  #349742 10-Jul-2010 12:46
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One of my mates did the exact same thing with his Core i7 about 5 months ago, one of the things we noticed is you really need to make sure the radiator is clean, after about 2 days of operation the CPU block ended up filling up with "Green Gunk" - We also ended up using Distilled Water + Antifreeze and now he's got his core i7 running at 4GHz stable (While running Folding etc)

The fan is not essential, you will find the heat loss over that distance will be enough to keep your computer cool to about ~50?C, if you have the fan running at the lowest setting it will cool it again to about ~35?C assuming your using about the same spec'd CPU Block.

My mate also has the GPU called, and has the folding GPU client + CPU client running, which tends to generate a heap of heat, so you should be able to achieve a lower heat than us :)

What could be a cool project for you is picking up a relay board or a Arduino and using that to turn on and off the fan from the computer itself.

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484 posts

Ultimate Geek

  #349793 10-Jul-2010 16:34
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Yep, I'm currently using rain water, after a month having been in the circuit there hasn't been any green gunk build up, but we'd stood the water for a month before using it.

I think I've got the one very slowly seeping joint sorted, but after a couple of days of water tightness testing I'll add the anti-freeze I got earlier. Don't really want to add it when there is any drips!

At this stage if I do use the fan I'll probably hook it up to a normal wall plug and leave it on low - providing the system can cool itself decently under load. With the amount of water in the loop it'll take a fair while to heat up without any heat loss and the UPS will force the computer into shutdown after about 20 minutes of a power cut.

Glad to hear someone else has taken the plunge with their i7 :)

29 posts

Inactive user

  #349867 11-Jul-2010 02:52
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Using rain water, that's so awesome!


484 posts

Ultimate Geek

  #352635 17-Jul-2010 12:55
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Finally got everything up and running. At the moment the temperatures are around 60 degrees @ 100% load @ 3.78Ghz without the fan.

With the fan on low that comes down to the mid to low 50s, which I'm pretty happy with - ends up with a 5 degree drop. What was interesting was how much warmer the memory gets than I had expected!

Will now be interested to see how things go as the temperatures outside warm up.


484 posts

Ultimate Geek

  #388142 5-Oct-2010 12:03
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I noticed I hadn't posted any photos. I haven't finished tidying up all the wires and cables, but here are some photos anyway:

Front view of my server, mainly used for Folding@home, but also as an HTPC.

Behind it is my webserver, above is the switch and just above where the white cable turns into a black cable is the UPS. On the joist opposite the switch is a powerboard from the UPS, powering the pumps, computers, switches and modems (so that in the event of power failure, I still have internet access). The area around where the red&black speaker cables head up is under the cupboard where we route all our cables between our ceiling and garage/ground floor. We also route cables up through the floor to the TV/entertainment center.

Next up is the view of the insides of the PC. At this stage there is still a heap of cables where they possibly shouldn't be, plus obviously, the fan from the Noctua CPU heatsink that I used before I went to water. That's just adding a bit of extra airflow over the RAM, the 6x2GB sticks make for a bit of heat. I might look at getting a proper memory cooling system at some stage. You can see the Zalman waterblock, along with the 10mm tubes running up. I've also put the Asus chipset cooler on due to the lower /turbulence airflow without the CPU fan. I am looking to add a 40mm fan to the Northbridge heatsink that can be seen immediately above the waterblock, but I'm investigating whether or not I can add one to the Southbridge as well.

The third image shows the water tubes leaving the case - the watercooling pass through holes of the HAF 922 really came in handy, though the 3 holes in the newly released 912 look even better. You can also see the reducers where the 10mm is connected to the main 20mm tubing. Slightly obscured is the reservoir, but more on that next.

This following photo shows the reservoir in better detail, you can also see the webserver in its less accessible location but I access it to manually power cycle it so that's all I really need. The reservoir is just a supermarket storage container with a few holes drilled in it (2 for the tubing, one for the power cord, all above the waterline). The green colour of the water is due to the antifreeze and the tubes are held in place as the holes are slightly smaller than the tubing themselves. The pump creates a degree of vibrations, that reverberate on the planks into the wall, so I need to replace the foam you can see in the picture (a cut up mousepad) with something more substantial.

Next is a quick photo of the rail that supports the tubing. Basically just makes sure the tubing gets from A to B.

Here is the tubing making its main vertical drop down to the cooling unit:

While the next two photos are of the cooling unit itself - first is the Radiator side of the unit, the second is of the fan side of the unit, Still need to work out how to fix some of the tubing.

And there you have it - what happens when you have too much time on your hands.

This current set up has allowed my computer to hit core temps generally under 70 degrees C while running folding@home at full load and at 4.2 Ghz, though to reach stable I had to increase the voltage a bit further and drop to 4.1Ghz, resulting in rock solid stability at about the same temperature.

As you can see from the last photo, there is room for me to add a second heater core if I wanted to, thus doubling the surface area of my cooling unit and possibly allowing for a higher volume of air to pass through the unit. If I did that, I would also look at adding a second pump, pulling water into the reservoir (as opposed to the current pump that pushes water from the reservoir through the system), to allow a better flow rate and greater redundancy.


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