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Cooling-The Definitive Guide

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Maximus Nickus

Senior Shaman
Oct 4, 2001
Milton Keynes, U.K.
Cooling-The Definitive Guide

Now every time I visit this Forum I see many questions of cooling, all of them are simple if you know what you are doing-but if you don’t then it’s a nightmare!
That is why I thought I would compile all the information I have on Air Cooling, Watercooling / Peltier's and wrap it into one guide.

This guide is designed to be easy reading, but don’t be fooled it will be useful for even the most seemingly perfect cooled rig.

On with the info!:D

Air-The Basics

The basic theory behind any cooling is to remove hot air particles and draw cooler air particles in, this is normally achieved by exhausting the hot air out of the back and top of the case and drawing cooler air in through the front. However there are many variations on this, now that I’ve explained the basic principal lets get on with it.

Air intake and vents

Anyone can stick a fan into the front of a case but positioning it to be effective is rather tricky, most vents in the front of PC’s have grills over them. This not only creates a whining noise with high power fans (due to the buffeting) but it also reduces airflow by as much as 65%.
Simple one this is though: simply take a pair of pliers and go around the edges till the grill falls out, once it’s removed you can sand down the edges to make it smooth (Careful, the edges are very sharp) but you cannot see it from the outside in most cases so it may not be worth the extra work of stripping down the case.

Now every front intake is positioned differently, whether it’s right at the bottom, or in a drive-cage it all makes a difference on airflow characteristics as well as which sort of fan you should use - Experimentation is the key.

Hence if there is only one intake you will want to make the most of it, you could either cut a 120mm intake with a Dremel, or simply use a high power 80mm fan. Depending on where it is placed can also affect this decision. If the fan is blowing directly on your CPU you may wish to use a slightly more potent fan than originally intended to provide that “extra” bit of airflow.

Another concern is Dust, regardless of case pressure (explained later in this thread) dust will accumulate, it insulates heat and causes less and less air to circulate through the PC, and is a mammoth task to clear up, so what are the solutions?
Basically I would use a homemade dust guard, something like a stocking, (Yes I know, no funny thoughts please!) placing this at the front of the case in front or behind the intakes (depending on which is more accessible for cleaning) will trap the dust but still maintain good airflow, obviously you want a compromise between air and dust, try out different combinations and monitor your temperatures.
Every system puts out different amounts of heat in different places so its really trial and error to get the best setup for your rig, just be patient and DON’T rush things.

Heres a great tip to maximize the use of airflow in your case, all you need to do is the following:
You will need 1 sheet of see-through glass or plastic the size of your case panel, and 1 incense stick.
Simply replace the side of your case with the sheet of plastic/glass and put the incense stick in front of the PC (not to close…do I smell burning!?) and watch the smoke move around your PC, this allows you to see “hot-spots” and other problems with your airflow.


There are many types of exhausts, from regular fans to PCI card blowers, they are all designed with one thing in mind, but are used for slightly different effects.
One thing to remember is the positioning of your exhausts, you want then as near as parallel to the intakes as possible to enable the most efficient airflow without any blockades, a common mistake is to put them in a cluttered area where they cannot “breath”, this causes very little airflow and makes that distinct whining sound.
I would position a PCI a slot blower under the AGP card (if there are no available fan apertures) coupled with a exhaust under and above the PSU, this should provide steady airflow.

Now, remember those good old science classes? When you were taught about convection, radiation and conduction? Remember how Hot air particles rise? Then there is no point in fighting gravity (who would win? :D) so exhausts at the upper level of the case are very effective at removing “hot spots” (spots around crowded areas usually in the top of cases, around the PSU and around cables where the temp steadily increases due to the absence of airflow) and exhausting hot air.


When building an effective cooling system you have to take into account the affects pressure has on a case, positive pressure (more airflow entering) will create a pressure of cool air and less dust will accumulate, however negative pressure (more airflow exhausting) with be exhausting more air than is available and thus as a result increases the dust level.
Therefore positive pressure is often the most preferred.
To achieve this simply have more air arriving than leaving! Now of course this isn't to say that Positive Pressure will give you a lower temperature than a more Negative setup, because it doesn't always. I would personally experiment with your fans (and the smoke method) to find out what works best for you!

Cables / Stopping blockage

Every case has problems with cables travelling into the flow of the air; this is an especially potent problem in Midi Cases.
The biggest problem is the IDE cables, they sit right in front of the intakes and they don’t bend very easily, I decided to buy some rounded cables however you can make your own (do a search here).

My technique for clearing up the airflow is to keep all the cables around the edges of the case using cables ties (over 100! :rolleyes: ) Basically every case is different so experiment with different configurations,
E.g. I tied my huge ATX power connector to a static plate mounted under my PSU.

How to lap a Heatsink

First the question of why?
Most heatsinks have a relatively rough base after their machining process (this is where thermal grease comes in). Even though it may feel smooth and flat, there are microscopic peaks and valleys which impede the transfer of heat from the CPU to the heatsink.

Now obviously with a rough base, only as much as half the heatsink may be contacting the CPU; thermal grease can fill these pits, but it's another substance for the heat to transfer through and it's not as efficient.

So we lap the heatsink to make it smooth so you get the best possible contact between the heatsink and CPU for maximum cooling. There will always be peaks and valleys, but lapping changes Mt. Everest to a small hill. Thermal grease fills these micro-voids, but the smoother the better.

Lapping can be performed on any type of Heatsink/Waterblock with a base, it can be Aluminium or Copper, (or a combination) just remember Copper sands much much quicker than Aluminium so be careful, and patient with Aluminium! (Most lapping takes about an hour for a Well done job)

Now for the process:
You will need some Wet/Dry sandpaper, if your heatsink is really bad a sheet of 400grit and one sheet of 600grit, if its not to bad just a sheet of 600grit.

Start by placing the sandpaper on a FLAT surface (a uneven surface is just defeating the object of the task, glass is often a Good Surface) pour a mixture of Water and a FEW DROPS of Washing up liquid (stops it sticking) onto the paper.
Now grasping the heatsink place the bottom (obviously!!!) onto the sandpaper, and make circular motions about 10-15cm in diameter, (it will be difficult and the heatsink will stick at first but as you progress and the bottom layer of the machining rubs off it will glide over).
Remember to press will reasonable force, every 100 or so strokes rotate the heatsink 90 degrees to make sure of an even surface.
Also every once in a while when the sandpaper looks very orange or silvery (the Metal particles) flush the paper with more water + Washing up liquid, keep doing this until the bottom of the Heatsink is smooth (test by running your thumbnail over the bottom and see if you can feel any obvious lumps). When its smooth you're done!!

A few notes + pointers now:
1> If the heatsink is really uneven to begin with (as I said above) start with a lower grit (more coarse) then after a Good 15-20mins of lapping check to see if all those Horizontal lines on the bottom are gone, if they are proceed to the 600 grit paper.

2> You may if you wish use a higher grit than 600 to finish with, some people even go to a 2000grit (so fine it would only take the shine and not the paint off a Mercedes body work) however it isn't necessary to have it so smooth, 600grit will give a smooth enough surface, going to a higher grit may make it shinier but you certainly won't get a performance gain (this has been debated many times).

3> After you have finished you may wish to clean the heatsinks surface with some Isopropyl Alcohol, I prefer to use this as it evaporates, unlike polish because you don't want a layer of anything depleting your Heatsinks performance.
For copper use a anti-tarnish solution you can buy, Brass-O is a popular one. its very Good at getting dirt out and making the surface as smooth as possible.

4> After you're finished apply some AS3 (this is the best Thermal compound) to the CPU's core as per instructions on www.arcticsilver.com and apply the Heatsink, you may be wondering why you're adding a Thermal compound if its another layer?
Well simply AS3 only fills the crefaces, if there aren't any it moves out the way, so make sure you apply an even thin coat on the CPU core, else it will be dripping down your core (Don't worry its not very dangerous (unlikely to get a short circuit) its just messy!)

5> 'Washing Up Liquid' is the Green Slimy solution used to wash dishes. It doesn't necessarily have to be this liquid but after trial and error I have found this works better than alternatives, its also safe on your hands and does not give out fumes.

You're done!

Water Cooling (H2O)-The new innovation

Water Cooling is the new technological advance for high performance cooling solutions, is provide supreme cooling at a near silent noise level.

The theory behind the performance of water cooling is how quickly water absorbs and dissipates heat, it also is readily available (I hope so!! :D).

Every setup is different but there are some principals to remember, one is to use Water wetter. This actually increases the thermal properties of water and protects components from corrosion and bacteria building up which is very useful in any Water-Cooled system.
The next is not always to buy kits, I have saved a lot of money by buying things separately.

Now the first part of a Watercooling system is the Pump and Reservoir which are normally the first inline, the things to remember are quiet good quality pumps are advisable (I found Eheim pumps are very good) and that the Reservoir is Air and Water tight. As for the pump you don’t always need to look at the GPH reading (Gallons per Hour) reading. You need to know how much pressure it can put out. It’s no use if it reads 400GPH but it’s only attainable when the back pressure is 0!!

I always go for 3/8th fittings so there is more Water to go around thus equalling better cooling, however this also leads to a drop in overall flow. So a more powerful pump is required.
½ fittings have less cooling capability but provide a higher flowrate so is more efficient for less powerful pumps. The only time this rule doesn’t apply is with HeaterCores, as they are designed so that whatever fitting is used it won’t affect its cooling performance.

(There are also two main watercooling systems, inline and normal. Inline is where there is no reservoir or Air in the system, just pump > pipes > Waterblock. The Normal setup is when a reservoir holds the Water (no bleeding to rid the system of air needed) and it simply flows around the pipes when turned on.)

Next inline is the Waterblock. There are many types but I’d always recommend Copper, I have found that the Maze 3 waterblock is a very hot competitor and so is the Gemini block. The Maze 3 can be found here and for a roundup of all the latest blocks look at Hoot’s superb front page article.
Some things to watch with waterblocks is how they are made, you would preferably want a solid block and maybe have it tarnish coated (like the BeCooling ones from www.aquastealth.com) I also recommend lapping your new Waterblock (as per previous instructions), as Copper has softer properties than Aluminium it doesn't take much time or effort, and it is well worth the small amount of time taken.

Now there are new breeds of Waterblocks (to complicate matters further), these are Direct Die (fluid injection) systems which don’t have a bottom to them so the Water flows directly over the Core. Now they sound great in theory as there’s no metal to slow down heat transfer but In real world circumstances this isn’t always better.
You see although water can disperse Heat easily and can hold a lot of heat, its getting the heat into it which is the key, Waterblocks use a lot of technology such as turbulence to force more heat into the water thus equalling better cooling. So remember to read a few reviews about the products first. Also they are much more prone to leaks and are a lot harder to set up. I've also known CPU's to go porous which inevietably leads to a broken CPU; So don’t say I didn’t warn you :D

Now after you have chosen a block choose a clamp, I use the hole mounted clamp systems but there a now screwdown solutions using all six socket lugs so pick whichever you fancy, generally the hole mounting system is much more difficult to attach (requires removal of Motherboard) but they are more secure.

Next inline is the Radiator/Heatercore. Generally speaking Radiators are smaller and less efficient. Heatercores are found in most automobiles but are rather large and not as smart (although they are cheaper and offer great performance). I personally went for this Heatercore as its small, smart and cheap, combining the good properties of each!
(Remember to test for leaks on a Heatercore out of a Car/Van.)

The Black Ice/Dangerden Supercube radiators are all superb options as well, it just depends on the severity of cooling you want, check the amount of Watts the Radiator can disperse and check how many Watts your rig puts out for a rough guide.

Now the extra’s…
First fans, you need a fan to disperse the heat collected by the Radiator, I find that two 65/85CFM 120MM fans are ample and near to silent. You may also consider getting a shroud which covers your radiator so the fan can pull/push as much air through as possible.

Now tubing, I go for Silicon Surgical tubing as it is strong, tough, and durable plus it returns to its original shape. It is also kink-proof in 80% of cases. But it’s your decision so choose wisely.

Clamps can be used to hold the piping on tight but generally speaking its held on tight enough by itself! (Takes a lot of effort to pull it off) so there not really necessary, although I use them for peace of mind.

Now let’s go a bit more advanced. Say you want to cool your GPU (Graphical Processing Unit) and maybe your Northbridge as well, well here’s some info.

Again spend the extra $$$ on Copper blocks, they provide superb cooling potential.
Now generally people run Watercooling in series, so that’s: CPU > GPU > Northbridge.

Now running in Parallel would be much more efficient.
So Y-Split > (1st Pipe = CPU/> 2nd Pipe = GPU) > Y-Split to connect them back together.

The reason for this is every component (CPU and GPU alike) are getting fresh water instead of getting the heated water from the other component. However the downside of this is requiring a pump of 300GPH or better and also you NEED 3/8th fittings otherwise there will be hardly any H20.
Now if you also have a Northbridge to cool simply put it in Series BEFORE THE GPU, as they don’t generate as much heat as the GPU your GPU won’t be heated up much (if at all), whereas if the GPU was first in series the Northbridge would be heated up.


The theory behind Peltiers is removing the heat from one side of the plate to another to create a sub room temperature, the only disadvantage is the side that draws the heat away gets very hot, thus it will require a Water Cooling system of its own just to cool it down!!
Peltiers are useful to reach a much higher overclock by the presence of a sub-zero temperatures, especially if your CPU is on its edge.

The only downside to this is that Peltiers require very high amp-age to run, thus a separate power supply is often needed just to power them. Condensation is also a drawback, and with refridgeration systems arriving pre-setup (although costing much more) Peltiers seem a daunting task.

Refrigeration systems use Phase Change Cooling to cool your CPU to sub-zero temperatures, they work on the same principal as your refridgerator and are becoming the choice for many people wishing to acheive sub-zero temperatures.
If commercially bought they also come pre-assembled which is also a plus.

The downsides are the costs, don't be suprised if you can't pick one up for less than $500.

The commercial systems available are the Prometia and the Vapochill, I presonally prefer the Vapochill as it has proved itself to be a reliable piece of kit, and there have been the odd problems with the Prometia's. However the Prometia's are more cost effective and in a lot of cases run cooler.

Both systems are also available pre-assembled without any case.

Useful links

Good prices on Water Cooling setups.
Great variety of Water Blocks.
One of the best suppliers in Water Block technology

>>>This guide should be of use to beginners through to experts, Peltier and Refrigeration I am non-experienced with so I have included little information.
If anyone wishes to add to this guide then please do.

Good Luck with your future cooling endeavours!

Nick Cade-Westcombe
'Maximus Nickus'
Last edited:
Hi I still have some questions. I can' t figure out what I am doing wrong. I have temps around 35-39C at idle. I have attached a drawing of my current case setup. Please halp if you can.:D

*my temps idle
cpu 35C gets as high as 39
case 22C always the same
room temp 68F

cpu 41C-42C
case 22C
Hi m_mike_k,

I can see some fundamental flaws with your airflow, there seems to be a lot of hot air exhausted (hence no rise in temp under load) but a lack of air coming in.

I would recommend that you try to bring more airflow into the case, this cool air should help bring your CPU temperatures down a bit.

Other than that your CPU temperature is good, the only thing you could improve is to do the following:/

1. Use a 80MM Cooler like the AlphaPAL8045 coupled with a high airflow fan.

2. Use AS3.

I am at 33C Max Load with the above.
If you have any more questions or doubts then please let me know!

Good Luck,
Maximus Nickus
Last edited:
thanks alot, I have been looking for a new hsf but have not found the right one yet. This might be a solution.

also, would changing the bottom intake to a 120 help? because there is no more room to add fans

You would also maintain a "low noise" system that way to!
I would say you have the right idea, one of the reasons for me getting H20 cooling is the noise.
The Doctor said it could affect my heaing in the long run.:eek:

Maximus Nickus
Mike, I had a very similar setup to yours, with a few differences. I have a 92mm Sunon up top and a 80mm Sunon intake at the bottom. Everything else is the same. I agree with the comments above regarding negative airflow. You can even your airflow out a bit by adding another intake fan on the side of the case. You should see a 2-3*C drop by doing that. You can also try a 60-80mm fan adaptor with 80mm fan on the CPU. I'm using a 50cfm 80mm Sunon for my setup (as soon as the adaptor gets here). You should see a decent drop in temps just by doing those two things. Bottom line: More intake airflow and better CPU cooling.
thanks for the replies
I will add another intake fan to the side panel and i will look into 80mm adapters or an alpha pal with an 80mm fan
Adapters are ok but sometimes they have there limitations, (depending on which HSF youre using) they can actually raise the temperature due to the effects of pressure.

They lower your temperatures in most cases but your HSF can only go so far, you can either buy a new More "efficient" one or get cooler air in.

In principal if the CPU is always 10C above ambient, you can drop the ambient or buy a new HSF.

Good Luck,
Maximus Nickus
is it possible to add a video jacket from becooling to a leufken water kooling kit (genesis?)

also do any of the video jackets fit on a g3 ti 200 visiontek?
Hi OC-Rubix-Cube,

I pressume you mean Video Waterblock, all leufken watercooling kits can adapt to fit these. (As well as 99% of WaterCooling kits!!!)

As long as you have the right fittings (3/8 or 1/4) all you would have to do is attach it with some extra piping and clamps to hold the pipes on!

You can do this either in Series or in Parallel (I think its called this!)

To connect it in Parallel you will need a Good pump (180GPH or better) and some extra piping and clamps, to connect it in Series simply add it after the CPU in the series!!

Video Blocks come with mounting bolts usually (if you specify), if your Gf3 doesn't have the mouting bolt holes then simply attach it with Arctic Silver Alumina.

Good Luck,
Maximus Nickus
Great guide, but you forgot the almighty silverprop :eek: You can import from them for about 20$ airmail, and the cyclone 2 beat the DD2, and the cyclone 5's are just getting released.
"Hail Maximus ... altimus studious magister de transferous calorimos de computeros! Bene fortuna!"

Lets see if I remember this: "Hail Maximus ... High Study Master of Heat transfer of Computers! Good fortune!" I think that is how is is translated, but it's in latin word order, and I don't want to put it in english word order.

BTW, it should be "Salve, Maximus!..." :D

I completely agree however. Maximus, you did a great job on this.
Black Hawk said:
"Hail Maximus ... altimus studious magister de transferous calorimos de computeros! Bene fortuna!"

Lets see if I remember this: "Hail Maximus ... High Study Master of Heat transfer of Computers! Good fortune!" I think that is how is is translated, but it's in latin word order, and I don't want to put it in english word order.

BTW, it should be "Salve, Maximus!..." :D

I completely agree however. Maximus, you did a great job on this.

You are correct ... "Salve" would have been more correct as a greating. Since it has been 27+ years since I took my one year in Latin in high school, I admidt, I was "winging it" a bit:) Perhaps I should have said "heil"? Or is that another type of Caeser/Tsar/Czar greeting? Heaven forbid it was of the "bad" Leni Reiphanshtal (sic on spelling) type "Heil"!