The Official Cooling Thread

[atom]

Since we now have a PC section in our forums I thought I would go ahead and make this thread. This topic is surely to come up many times.

What is the best way to cool your computer? Sure, you can spend the bucks (thats slang for dollars)  on some fancy water cooling system that sounds like a fishtank pump after a year or two... Or you can do these methods.

.::Air cooling::.
This is the most used method and probably the most practical method. Consist of a heatsink on the chip, a fan mounted on the heatsink, and a fan or duct to bring in cool air. Can have really good results. The heatsink works by having a very heat conductive material attached directly to the cpu. The heatsink has many fins to expose more surface area to be able to conduct more heat to the air. The air that is now hot from conduction is pushed out by the fan and cooler air is brought in.
Pros: Cheap, Reliable, safe, effective
Cons: Very noisy, dusty, adds a couple dollars to your electric bill

.::Heat Pipe cooling::.
This is a pretty neat way of cooling a computer, although it is often combined with some air cooling. Heatpipes are a plate connected to the cpu, with pipes coming off of the plate that reach up to a heatsink. Their is often a case fan to remove the heat given off by the device. Some even have a fan mounted right on the heatpipe cooler which defeats the whole purpose but they are out there. The way a heatpipe works is that the plate is clamped down to the cpu. The heat reaches the plate and inside the pipes is a liquid with a low boiling point. It may be alcohol but I honestly don't know. Now when this liquid is heated, it evaporates, and when something evaporates it makes the surface it evaporates SUPER COOL. This is the same effect you get when it is windy outside, the moisture from your skin evaporates and you get really cold. So the evaporated molecules float up to the top of the heatpipe, hit the top and cool down. As the molecule falls back down to evaporate the heat is transfered to the heatsink and then to the air.
Pros: Not very costly, safe, EXTREMELY quiet (no sound at all), uses no power
Cons: Cooler has to be facing the right direction for evaporation (pipes upward), isnt as effective

.::Water Cooling::.
Fancy! Water is put through a pump and shot around the pc through little plastic tubes. The water then runs through plates attached to the chips. The heat transfers to the plate, then to the water. The water continues through the tube to a radiator to cool down. The radiator is basically a heatsink, sometimes the heatsink has a fan.

Pros: Effective, looks neat, quiter then air cooling
Cons: Dangerous (leaks on your motherboard?), unreliable (pumps break down), consumes a lot of power, and EXPENSIVE

[atom]

And just for some glory shots, I tweaked my cooling a little bit. You guys post what your running too. I am using a sunbeam air cooler, and as you can see its nothing fancy from the stock AMD cooler. Look here. I removed the blue LED fan as it had bad bearings and was shaky and put in a red LED fan.  I have a duct with a fan on it bringing air directly from the outside of the case to the cpu cooler. I also have a case fan on the front to remove the warm air. All fan speeds have been reduced to be quieter and so that the air doesnt pass through the cooler to fast to conduct the heat. What probably makes the biggest difference is that I used high quality thermal compound, "Arctic Silver". I also took care to make sure their are no air bubbles.

In this pic, only the 23c is what matters, my cpu. My two hard drives are old and are not SMART enabled, that is not the actual temperature. I also set my cpu to its normal clock for this test. The two fans for the case are connected through power supply and not the mobo, so the speed isnt reported.

[TJ_Kat]

You missed a few cooling methods...

.::Peltiers::.
Basically, what a peltier is is a polarized metal plate with an electric current running through it that you attatch directly to the cpu. The polarity of the current causes all the heat in the plate to be drawn to the side of the plate away from the cpu. That side becomes extremely hot, while the side touching the cpu becomes cold. However, you need to combine this with some other cooling method, since if the peltier isn't properly cooled, the whole thing will become very hot very quickly, and it will fry your cpu. It also serves the function of eliminating the possibility of condensation on the cpu (and also on the water block in the case of liquid cooling).
Pros: VERY effective. Eliminates condensation.
Cons: REQUIRES a more standard method of cooling with it. If the peltier's cooler breaks down, your cpu is toast.

.::Liquid Nitrogen::.
Or some other high performance coolant. Similar to water cooling, but it requires a compressor somewhere in the loop.
Pros: There are no more effective cooling methods.
Cons: And you thought graphics cards were expensive...

.::MiniFridge Case::.
This is one I play on doing someday when I actually have a PC worth super cooling. Basically, you can get a decent sized minifridge for less than you can a high end PC tower.
Pros: Combined with standard air cooling, this is probably more cooling than the average person will ever need.
Cons: Requires a LOT of modification to the fridge. It's HUGE. It will use a lot of power.

Some misconceptions about water cooling:
- It's "EXPENSIVE" ; In the past, yes, but as it's become more mainstream, there are companies offering complet kits that are comparable in price to higher end air coolers. And to DIY, I consider www.dangerden.com to be very reasonably priced for all your liquid cooling needs.
- Leaks will destroy everything! ; Yes and no. If you shell out a bit extra and get some distilled water, there's not problem. Pure water is NOT conductive. it's when you add all the impurities of naturally occuring and treated water that it becomes highly conductive. But since most people put in additives so the water looks cool with their case lights, make sure everything is pressure tested and in good shape before putting it in the case.
- Unreliable (pump breaks down) ; If you set up a water system properly, you don't even need a pump. Admitted, pumpless circuits are not as effective, however, they are more than enough to keep your cpu alive until you can fix/replace the pump.
- Consumes a lot of power ; No. A small submersable water pump doesn't use that much power. A high end radiator draws no more power than 2 good case fans. A more standard radiator would use no more power than the fan in a standard air cooling solution.

Now, what is the "best" cooling solution? Depends how you use your computer. For an "average user" whatever comes out of the box will be fine. Same goes for a recreational/avid gamer; unless you have a newer P4, or an older Athlon. If you live in warmer climates, these have a tendancy to shut down from overheating for many games. If you're doing any overclocking, you should invest in a water cooler. While you may be able to overclock with a good air cooler, you will prolong your cpu life with water. Even the worst pumpbased water cooler will be more effective than the best air cooler. Now, if you're cracking government mainframes, you probably already have a $2000 quad (or more) mobo, and the cost of nitrogen cooling shouldn't be an issue.

IMO, the one that gives the biggest bang for your buck would be water. Even under average use, the increased cooling offered by a water cooler will prolong the life of your cpu.

[atom]

Well there you go, theres some more insight. I have also considered something similiar to the mini-fridge idea. I did not know about the distilled water thing, thanks for the info. However I must disagree with you saying if you overclock you need water cooling. Overclocked my cpu is about 26 degrees with my new adjustments, and it is overclocked to the max it can go without crashing. At 26 degrees it obviously isnt crashing from the heat.

[Aidan]

Peltier effect devices are not metal plates - they're usually in a ceramic package. In my opinion, they're not really very effective - they're highly inefficient devices. If you want to pump any significant level of heat, then you're usually better off looking at phase change rather than peltiers. A peltier element that can pump 200W worth of heat will add it's own thermal load (typically over 300W) to the output. That means your cooling system has to be able to cope with 500W of heat, whereas a typical CPU only kicks out less than 100W of heat. Additionally, you have to add a power supply capable of running the peltier element. As far as I can see, peltier element cooling has really had it's day.

Liquid Nitrogen (LN2) cooling just requires LN2, and a suitable container mounted on the CPU. The basic foundation of LN2 cooling is that LN2 evaporates at a very low temperature, and hence will cool whatever it's in contact with. The disadvantage is that once it's evaporated, you need to refill the container. It's often used for a 'one-shot' attempt at high speed systems, where it doesn't matter if the system can only run for 10-15 minutes. It's cheap enough to buy LN2, as long as you have a suitable container (dewer flask).

Phase change (AKA fridge/freezer) is a highly effective method for cooling systems, but is fairly expensive. Phase change systems typically don't take too much power when running (150W), compared to peltier based systems. They tend to be a bit noisy though. Whilst it is possible to build your own, you have to be very careful of laws in your territory. Many countries require anyone who's filling or empting the system of it's refrigerant to be a licensed HVAC engineer.

About water cooling:
Whilst pure water is not conductive, expose it to anything containing metal or mineral, and it's no longer pure water. It's recommened that you use additives to prevent organic growth, and to protect the system from corrosion. I've yet to see a pumpless system capable of cooling anything but fairly trivial heat loads. A suitable water pump is not likely to draw more than about 30W or so. If you put together a system properly, and don't take short cuts, you are unlikely to find it leaks or fails. Reservoirs are definately not required, and have no place in a modern water cooling system.

That's my �0.02 at least!

[TJ_Kat]

Ah, but I said "should" not "need"; an important distinction.

The important thing to understand about IC's (including cpu's) is that the more heat your run through them, the shorter the life they will have. So by overclocking your cpu and letting it run hotter, it's going to have a shorter lifespan than if you ran it at it's rated clock speed.

Of course, considering the rate people are upgrading these days, this probably isn't a big concern for most.

Now, as a cautionnary note, you don't want your gear too cold either. Hence why I would still advocate water over nitrogen if cost wasn't an issue. Your ideal temperature for running electronics is 65 degrees fahrenheit (~18 celcius). The closer you get to that temperature, the longer your electronics will last. That's why computer labs/server rooms are usually cooler than everywhere else in a building.

I did my homework on this stuff back when I was still drooling over taking a "top of the line" 1.2ghz athlon up to 1.6ghz.

Aidan: Thanks for the correction on the peltier. However, I have to disagree that they've had their day. They still serve an anti-condensation fuction, which can become an issue with alternative cooling.

I also disagree about resevoirs having no place in modern cooling systems. A small submersable aquarium pump is cheaper than almost all other water pumps suitable for the job. Also, water loss in the system is inevitable. A resevoir makes this easier to monitor, makes sure there is still no air in the heat exchange part of the circuit despite the water loss, and it makes it easier to refill.

Of course, these are just my personal preferences.

[atom]

Aidan is always a useful source of information. Try to keep this as a "hey did you know" thread instead of a debate. The LN2 idea reminds me of a silly idea I had for my system. I dreamed of a pipe within my heatsink connecting to the outside of my case in a big U shape. I then imagine if in the middle of gaming my cpu got a little hot I could squirt in some compressed co2. This however would be pointless as it would just raise back up after my squirt.

[Aidan]

With CMOS circuitry, like CPUs, the maximum speed is inversely related to the temperature. IE, the higher the temperature, the lower the maximum speed the device can work at. That's how people have got Pentium 4 chips up to the 7GHz mark!

Any device that takes the temperature down to the dew point will suffer condensation. That includes peltier effect devices.

[atom]

Yeah, I was going to say that too but I didn't want to start a whole argument. I really dont want this thread to turn nasty.

[Aidan]

My experience with server rooms is that the aircon is set to that temperature, not because the electronics works best, but because it's a good compromise between power consumption and localised heating issues. Most semiconductors work far better way below zero than they do at ambient temperature. Other components (like some capacitors) do not like being below zero, as they use water internally. Most don't care one way or another.

One benefit of running devices cold is that thermal noise is much reduced. Thermal noise can make the difference between a clear signal and a signal swamped by background noise.

[TJ_Kat]

I never said they don't work better at cooler temperatures, I said it shortens their life span.

[Aidan]

Generally, the higher the temperature, the shorter the lifespan as long as you ignore thermal cycling. However, generally silicon devices are quite happy at elevated temperatures (>50C) for many years at a time. Other parts of the motherboard are far more likely to have failed before the CPU itself fails. Parts such as electrolytic capacitors in the power supply section come to mind!