The Asylum

PC Water Cooling (from a complete beginners point of view) - an article I wrote back in September 2007. Things have changed since then though, but that's for another artilce :)

My experiences and some general advice follows:
This aspect of the PC inners has always interested me to some extent, and with recent (ish) advances in this technology, it's open to anyone really.
What pushed me into actually installing some was the purchase of an Nvidia 8800 GTX graphic card. Now with the stock cooling on this little beast would run at around 80 DegC, with all that heat belching out under my bench desk, I was starting to cook :)
So after some extensive research utilising that fine tool known as Google, having a quick chat in IRC with a few people I know who've installed their own, I plucked up the courage and took the plunge.
Now I will suggest to anyone thinking about doing this themselves, have a good look around and read up as much as you can, take this article as a taste of my experience.
There are a fair number of complete kits available now as well, however none of them were entirely suitable for my needs. After working out the additional costs (mainly for the 8800 GTX water block), I came to the conclusion that I may as well pick my own components.
Now this is the tricky part - what tube size, what flow rates, what fittings argghhh :)

You'll need the following components to cool your CPU and GPU:

A pump
A reservioir (highly recommnded)
A radiator with fans
A CPU water block
A GPU water block
Some tubing and fittings
Some fluid
Some determination and strong will :)

The pump:
Now the flow rate part I pretty much ignored in my calculations and just opted for a pretty decent pump (according to reviews). I'm sure there are lots of views on the technical issues of choosing a pump (based on head pressure and flow capacity), mostly based on whether you want a fast or slow flow system, physics tells me that the faster the water is flowing the greater heat transfer properties it has, however it's entirely up to you to decide. In my case the choice of pump was a Laing DDC-1T Pro with a Petras Tech DDCT-01 Derlin Top. This pump comes complete with a 12v molex connector and a pump speed run signal (which you connect to your CPU fan header) so you can shut down, or raise a warning, if the pump stops for any reason.

The reservoir:
Not only does this provide a fluid buffer for your whole system, but it also acts as an air trap, taking all the bubbles out. Due to this property I chose a reservior that fits in a 5 1/4 drive bay, at the highest point in the system (air rises in water don't ya know) :)
Being a bay type makes it a lot easier to fill, and maintain the system over time
When fitting the tubing make sure you allow enough length to cater for sliding this out to expose the fill hole.

The radiator:
I'm sure there's a lot of science that goes into these, however I just opted for one that looked like it would do the job: an Alphacool NexXXxoS Xtreme II revision 2. This radiator accepts two 120mm fans. My deciscion was also swayed by being able to fit a fairly large sized radiator inside my case. You can have more than one radiator if you wish, and can also fit these outside of the case.
With regard to the fans, I opted to balance noise level against air flow, so went for the maximum air flow I possibly good at around the 20dBA mark, namely two Xilence Red Wing 1400RPM fans. These offer a rated 68.00 cfm (cubic feet per minute) at only 21.2 dBA - nice lot of air flow for very little noise. I personally couldn't find anything better than those. These will either draw or push air through the radiator to cool the fluid down.

The CPU block:
Alphacool NexXXxoS XP Bold Highflow for socket 775. CPU water block. My choice more than likely based on marketing blurb rather than any technical basis. A few reviews cropped up in my search and it seemed like a pretty good bet, so I bought one :)
Fitting this required the motherboard to come out, but otherwise was quite straight forward.

The GPU block:
Now I did spend a fair amount of time reseaching this, after all it was my graphic card which prompted this whole project anyway :) So after checking various product reviews and performance figures I bought one of these: EK-FC8800 GTX block.
Fitting this was quite fiddly. Quite a few small thermal pads to fit and lots of components to paste. Read a bit more at further down :)

Tubing:
I think this really boils down to personal preference, as there are a few different sizes.
You're bound to pick up some tips about the flexiblity, or lack thereof, of all sorts of different tubing. Based on the type of fittings I opted for, I chose 10/8 mm tubing. This means 10 mm outside diameter with an 8mm inside diameter, therefore having a wall thickness of 2mm. One thing you really should be wary of: you can't bend this stuff too much. It's pretty versitile, but it won't bend at a ninety degree angle for example. Any extreme angles you may have to look at using right angle fittings. More on tubing installation a little further down.

Fittings:
Barbs, push, compression, oh the choices the choices :)
Push connectors I'd pretty much written off before even starting - didn't seem at all safe to me. Barbs - I think these also go by a different name but that escapes me right now. With these you push the tubing over a tapered end and clamp it in place. I didn't opt for these as I thought things may get too tricky to tighen the clamps when all the kit is fitted inside the case. So I went for the compression fittings. These operate in a similar fashion to the barbs, ie. you push the tubing over a tapered end, but this time the clamp, as it were, is more or less part of the fitting, you simply tighen it up on the tubing. It turned out that this was probably just as awkward as clamps :) If you have some strength in your hands, then you probably won't need to resort back to the tools to tighten these up.
These fittings also need to be screwed into each of the components via a G1/4"; thread. The compression fittings I used came complete with an o-ring seal. The general advice here is to tighten them by hand and then only snug them up maybe quarter a turn with a tool.

The fluid:
You actually can't really just use tap water here. You'll need to consider the potential of a water cooling system springing a leak and covering some electrical components. Tap water is a no no
I found much debate on this subject. I decided to go for the Fesser One product for a few reasons: Extremely low conductivity - the small likely hood of any future leaks *shouldn't* destroy my PC. Anti algae agent - no green stuff should grow in this. Corrision protection for copper, aluminium, brass and nickel - seeing as these are some of the key ingredients used in water blocks, a wise thing. Has a good dropper cap to aid filling and is UV reactive.
I went for the UV option as I thought this feature may help spot any leaks (I have some UV CCD lamps inside my PC).

Some determination and strong will:
Now this is where you come in :)
I will tell you that I was really scared of doing this but actually really enjoyed compiling and fitting it all.

The actual plumbing:
Measure twice cut once I kept hearing :)
Now there is some confusion on the order of the parts, in so much as, apparantly it actually doesn't really matter where in the system the radiator is plumbed. However I drew the following consclusion:
Reservior -> Pump -> CPU -> GPU -> Radiator -> Reservior
Note that a few components have a specic inlet and outlet port which you must obey!

Filling and testing:
Ensure that you unplug the power from the motherboard and all the other components before testing.
I was forunate enough to have a spare ATX power supply kicking around for testing purposes.
Make sure the pump has power available but not turned on yet.
You can start ATX power supplies by shorting out the middle green and black pins together. Unless your power supply has a seperate on/off switch I wouldn't suggest you do this just yet.
To fil the system, I simply filled up the reservoir. It was at this point that I encountered my first problem - the fluid wasn't running down to the pump. I spotted an air lock in the reservior. This was cured by fitting the lid back to the reservior and tipping the whole PC on it's end so the fluid ran down. I had to do this a few times actually before the air lock vanished. This got to a point where I couldn't fit any more fluid into the reservior, so time to pulse the pump on. Don't run the pump dry.
Paranoid about leaks I kept checking every second for any signs :)
Fluid whizzed round the system and emptied the reservior, so topped that up again and repeated.
At this point I also noticed a very tiny leak at the outlet of the pump. With a little more tightening of the fitting this was cured.
I got to a point where the reservior was full and the system running merrily.
To aid getting the air out, you can switch the pump off for a few seconds, then on again and let the system run for a few minutes. For any stubborn air bubbles you may have to tip the case around to shift them (make sure no fluid can come out if you're going to do this though).
After ensuring there were no more obvious leaks, after about 30-40 minutes constant (paranoia) checking, I let the system run overnight for a good 12 hours or so.
No sign of any more leaks (touch wood) and my PC is ready for action again.

The results:
Well as I mentioned earlier, my graphics card (GPU) was running at around 80 DegC.
I'm extremely pleased to tell you that the water cooling has shaved over 30 DegC off that. Now running at around 47-48 DegC. Much much better.
The CPU temp has also dropped around 10-12 DegC - idling now at around 31 DegC, with a load temp of around 38.
So not only is this system considerably quieter (in fact I can barely hear it) but performs amasingly.

The odd and fiddly bits:
The UV reactive fluid actually isn't as reactive as I was lead to believe, to the point where it doesn't seem to be UV reactive at all.
My CPU block was missing some crucial nuts - make sure you check your equipment has all of the necessary parts before you start to fit anything.
Removing the existing heatsink and fan from the graphic card was a nightmare. It just wouldn't budge. With some gentle persuasion it eventually came off however

NOTE - you will without doubt invalidate any warranty with your equipment if you install a water cooling system. Some graphic cards actually have a water block already installed. We may see this move onto CPU and other component coolers in the very near future.

Recommendations:
The folks at watercoolingshop.com  whos service has been awesome. Brilliant delivery and prompt service. They'll have everything you'll need for a water cooling setup.

I hope this article has been helpful to you, and best of luck.