Watercooling Thoughts

Some musings from one of our readers – M. C. Misiolek

Ed Note: For another view, go HERE. Critical comments encouraged, but no flames; pls
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The concept of “water cooling” a PC has been around for a long time. Diehard “overclockers” have been successfully building water cooling systems for extreme applications for years, long before they ever became fashionable among mainstream PC users.

Applying this technology to a Micro is no different than it would be on any other computer. However, like everything else involving this project, there are decisions to be made, some “creative re-engineering”, and the inevitable trade off’s.

Before diving head first into the pond, there are a few things you should keep in mind:

Water cooling will do little, if anything, to increase the performance of your average home PC.

The benefits of this technology are reserved mostly for “overclocked” systems which generate a great deal of excessive heat. Overlocking a PC involves running a processor at a faster speed than it was designed for. Not all processors can be overclocked. Two processors of the same make, model and rating may give totally different results when overclocked. A lot has to do with its architecture, the way it was manufactured, the amount of impurities it has in it, and so on. It’s not just the processor you have worry about, either. The memory and video must also be overclocked as well. This is a whole separate technology you need to educate yourself on.

Water cooling a PC is relatively expensive.

Some manufactures offer “kits” which start at around $200. I bought the Swiftech one a few years back and it didn’t even include the water blocks. If you expect to archive optimum performance, not only do you need to water cool the processor, but the chipset and the video card as well.

I took it one step further by including a jacket for the hard drive and Southbridge chips. Water blocks sell for around $35 – $100 each, depending upon their specific application. Generally speaking, a good water block for the processor will cost the most. Add cooling additives, hoses, clamps, and a bunch of other things you don’t think about until you need them, and you’re looking at something closer to five-hundred bucks by the time you get it all up and running.

In many respects, water cooling is still very much a “cottage industry” with lots of people selling components that are – to be kind – less than useful. Some of the stuff they’re pushing is out and out “snake oil” and they should be ashamed of themselves for even thinking about selling it to people. To make matters worse, just about every supplier I know of out there will not accept returns on any water cooling products – you buy it, you own it.

The biggest problem most people “new” to water cooling will face is:

Who do I believe?

Again, to many people out there, the promotion of water cooling and all of its various components is a “business”. Some people have no idea what they’re talking about: others are just plain old “liars”. No matter what claims a supplier or manufacturer may make, there are two things to keep in mind:

  1. A water cooling system will always follow the rules of fluid dynamics

  2. The normal operating temperature of a standard PC water cooling system can never be lower than ambient temperature

If room temperature is seventy degrees, the temperature of the fluid pumping through your system will never get lower than seventy degrees.

If you’re looking for a lower operating temperature, you’ll need to apply some sort of refrigeration – such as a thermoelectric cooler. They require a separate power supply to run and will give you headaches with condensation. I’d like to try Prometia cooler unit, but hooked up to the reservoir, not the processor. Chill the fluid running through the whole system down to say, thirty-nine degrees, maybe?

At a certain point it becomes impractical, if not down right silly to push it much further. The law of diminishing returns kicks in – especially for a day to day working computer. Right now I’ll stick with a plain old 3/8″ tube water cooler.

There are two basic configurations of water cooling systems:

The first approach is to throw everything into one box.

This is usually done with towers and others large capacity cases. The advantage is that you end up with a nice clean single unit installation that you can move around if you want to. It provides protection for the hoses, pump, and radiator. It looks nice, too. The drawback is that it adds a lot of “clutter” to the inside of the box. These components tend to radiate heat inside the case as well.

The second approach is a “half in – half out” setup.

In this configuration, all the mechanicals are either hanging on the outside of the case or are stuffed into a second box of some sort. This is the configuration I went with on my project. It gives it sort of a “post apocalypse” industrial look. The advantage here is simplicity, one hose going in – connecting to each water block in series – one hose coming out – a lot less “clutter”.

This reduces the amount of surface area radiating heat inside the case. It cuts down on the leak hazard, too. You don’t really want any, but if it’s gonna’ happen, I’d rather have a fifty-fifty chance of fluid leaking on the floor instead of a hundred percent certainty of fluid leaking inside my case. The drawback is that all the hoses and mechanicals are exposed. Someone could bump into it or snag a hose.

There are a couple of really silly ideas floating around out there about increasing the performance of a PC water cooling system. One has to do with so called “Swirl Technology”, putting baffles or intricate channels in water blocks to increase their surface area.

Keep in mind the normal operating temperature of a standard PC water cooling system can never be lower than ambient temperature. Will it help to get the system closer to ambient temperature? Maybe; some water blocks are more efficient than others, but I doubt it would be worth any extra money. A good brand name water block with a copper core is all you need.

Another bright idea is to use oversized hoses and fittings. This is supposed to somehow increase efficiency. Not so. One of the rules of fluid dynamics states that for any given diameter of pipe or hose, only a finite volume of fluid will pass through it at a fixed rate. The standard size of hose used in most PC water cooling systems was 3/8″. There are systems being offered now with ½” tubing, and that’s fine.

However, if you start off with a 3/8″ system and add a ½” hose from say the reservoir to the radiator, the system will only “see” the smallest diameter hose – 3/8″. The flow rate will remain at the 3/8″ level.

Also keep in mind that water blocks are “timed”. Depending on the surface area of the water block, a specific volume of fluid must pass through it at a specific rate for optimum heat transfer. The water block itself can only accommodate a set volume, it has a built in restriction – so don’t waste your time. Use the correct hose diameter intended for your system.

The most ridiculous waste of time and money I’ve ever seen in a PC water cooling system is the use of “Y’s” and “T’s, or separate hoses to each individual water block. Once your system is up and running for awhile, the temperature of the fluid pumping through it will stabilize, hopefully as close to ambient temperature as possible. One simple loop, connecting one water block to the next in series with very gentle bends in the hoses is the best way to do it.

I already had part of a Swiftech kit, which included a pump, radiator, two fans and some hose – but no water blocks. So I went with “Innovatek”. They sell a processor water block that snaps in place using the stock fan mount. Most chip set water blocks have a bracket which is held in place by screws.

This requires drilling holes in the motherboard – very scary. I had the drill in hand, but after looking down at all those little pathways printed on the board I just couldn’t do it. Luckily the Northbridge chip set had a heat sink on it. I took it off and used a couple of plastic ties to hold the water block to the heat sink hard points already there. You don’t need five-hundred pounds of pressure here; just enough to hold the water block in place. Let the thermal paste do the work. I used Arctic Silver.

The Southbridge chip set was a different matter – it didn’t have a heat sink. I’m not sure if it even needs to be cooled, but I put a water block on it anyway. I glued the plastic mounting screws to the motherboard upside down using thermal adhesive, then secured the water block with plastic nuts. Be careful here.

Most epoxy-based adhesives, including Arctic Silver thermal adhesive, will conduct, or even hold, a small charge. A glob of epoxy on your motherboard could act like a “capacitor”, if it makes contact across a circuit, changing its value. I used a “non-conductive” thermal adhesive. You could use the same stuff to hold all the water blocks in place, but it would be a “permanent” installation.

The Geforce 4 video board was a snap. I just took off the heat sink and slapped on the water block, using plastic nuts and bolts through the same holes used by the heat sink. The hard drive was easy too, although a little messy. All I had to do was mix up some non-conductive thermal paste that came with it, then slap on the water block. That’s all there was to it.

Now, just hook up the hoses, install the pump, fans, radiator and add distilled water with some additives. Some folks don’t even use a reservoir. I didn’t use one when I “leak-tested” my set up, but I’m using one now. It’s a little easer to get the bubbles out. Ether way, it’s your choice.

I hope this little primer will give you some insight into what’s involved in setting up a PC water cooling system. As you can see there is no real mystery to it. Water comes in, water goes out. That’s it. Keep it simple, use the best brand name products you can afford, and don’t get sucked into all the hype.

M. C. Misiolek

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