A Guide to Air Cooling, or at least some stuff to think about

A fan is not a fan is not a fan, and your processor is not the only component that needs one near it. Consideration should always be given to system-wide cooling for the sake of stability and the lifespan of your components. It doesn’t have to be extreme, expensive, or loud, but it needs to be something.

Take a look at just about any standard ATX (whoops, looks like next year I’ll have to start examining cooling for BTX boards) motherboard. Draw a line (not literally, of course) from the lower front of your board to the upper rear. It is no coincidence that this line crosses or is very close to many major hot-spots, mainly your chipsets and processor. Now, lay your board in your case, if it is not already in one, or imagine it in one. Do you have mounting for an intake fan at the lower front and for an exhaust fan at the upper rear? That's no coincidence either, and it's no coincidence that the two coincidences I've mentioned coincide (that's three "coincidences" so far).

Air has some of the same dynamics as water. It will generally follow the path of least resistance toward its destination, but will to a degree expand to fill unrestricted space depending on its density/mass/volume. Together, equally powered fans in a case supporting lower-front and upper-rear intake and exhaust fans will create a mainly diagonal path of airflow, even though the fans are sitting parallel to each other and are vertically offset. To some degree, the lower-front intake fan will blow on the PCI cards, cooling those often-neglected components, but the air being pulled out of the case by the exhaust fan near the processor has to come from somewhere, so the intake air provided by the intake fan is mostly redirected diagonally past many vital components on the motherboard and the processor.

In-and-out diagonal airflow is the most efficient, simplest, cleanest air-cooling setup, and an excellent base for any additional cooling that could be needed. With only two fans, no other fans interfere with the direction of airflow, keeping the path of airflow predictable and simple. The diagonal path ensures that mostly fresh and cool intake air makes it to the processor and is pulled through the heatsink by the exhaust fan. Using only two fans saves power. Additionally, a standing blow-through CPU cooler such as the AeroCool DP-102 will operate without fighting the diagonal path of airflow, and will in fact benefit greatly from it. As far as keeping the case clean goes, some people just like to leave their cases open, which allows a lot of dust to settle in. A closed case with a two-fan intake/exhaust setup means you need only put a dust filter (and really, even just a stalking should work fine) over your intake fan in order to protect your thermal exchange surfaces from collecting dust, which could reduce the amount of heat your heatsinks and such can release into the passing air, eventually causing your heatsinks to become hotspots themselves rather than transfer points for that heat. More powerful fans may also prevent dust from settling, but if left unprotected the dust may still settle in the fans themselves.

For people with chronic heat problems, two fans may not seem like enough. However, tacking on more fans may only increase heat. Fans themselves do in fact generate heat, as does any electrical device, though they may move cool air into the case, providing an overall benefit. Adding more fans without giving things a hefty amount of consideration could draw more power from your PSU, generating heat there and on the fan itself, without providing enough benefit to combat the generated heat. Additional fans may also work against the already existing direction of airflow within the case, making the new fan useless and decreasing the benefit the old fans provided.

Before one considers simply throwing more fans at a heat management problem, one should check a few things. Are all heatsinks properly mounted? Heatsinks can’t transfer heat to the passing air if they are not receiving heat from the components on which they sit. A heatsink firmly and flatly mounted against a hot surface, with a good thermal compound (such as Arctic Silver 5, though what is “best” is up for debate) filling the spaces between will always perform best. Is the thermal compound in use old, misapplied, dried out, or even non-existent? Fix that. Many articles to be found online discuss proper application technique for thermal compound, so I will not. Is there a mess of cables impeding airflow? This can be remedied by placing obstructive cables out of the way. Some cases even have sideways hard drive racks, allowing the cables to rest along the side of the case and out of the way. If obstructive cables are still a problem, one should either buy round drive cables or modify their flat drive cables to be flat. Other smaller wires can be zip-tied to the frame of the case in order to stay out of the way. Is your case stuffed in a dusty, cramped area? Move it somewhere that will allow its intake fan will be able to get cool air and its exhaust fan will be able to expel hot air without it being recycled by the intake fan. If the case can’t be moved, set up some ducting. It is not unheard of to connect a duct from an air conditioner to the intake fan on a computer. It does, however, look ridiculous.

If heat is still a problem, do not yet resort to adding fans. Weaker fans should be replaced with more powerful ones instead. The Vantec Tornado line of fans, widely recognized as the most powerful in their respective sizes that can be found on the market, come in 80 and 92mm variants. Under normal circumstances, the noise generated and power used by these fans is unjustifiable, and those that tend to use fans such as these are either deaf, overclocking their equipment heavily, or operating their equipment in an extremely harsh environment. In the two latter cases, alternative cooling solutions would be more prudent, although more expensive, than excessive air-cooling.

As loud as the industry leading Vantec Tornado fans may be in generating the airflow that they do, there are still alternatives that offer comparable airflow at reasonable noise and power levels. Bigger fans – 120mm if you can mount them – usually perform best. A larger fan can push more air than a smaller one operating at the same RPM and using the same amount of power. This means that a larger fan can operate at a lower RPM, generating less noise than a smaller fan while probably still blowing more air. The difference can be seen in the specs given with most fans. The average 80mm fan may push 20 to 40 Cubic Feet per Minute (CFM), while the average 120mm fan pushes from 50 to 100 CFM. Large fans are where cooling and silent PC enthusiasts will find common ground (alternative, silent cooling methods aside).

If after all this heat still seems to present a problem, keep in mind that sometimes thermal sensor readings are inaccurate. Your BIOS may be in need of a flash in order to properly read the temperature of your processor. Other thermal sensors connected to the thermal sensor pins on the motherboard may be misconnected, damaged, or misplaced. Beyond that, the advice of a certified technician may be sought. It may be found that heat wasn’t the problem all along. Don’t go selling your new cooling equipment, though – you might as well overclock while you’ve got it. Even if you damage your equipment doing it, it was bound to be outdated in a month or two anyway.

If more cooling is still needed for whatever reason – extreme overclocking, hot environments, broken AC… yes, more fans and various tweaks can be added. If you don’t need any more cooling, you need not even bother to read any further. As was stated before, a lot of times it won’t present much benefit, and probably will overcomplicate things, but there are ways to throw in all this extra stuff without messing things up. For a hot running PSU, an accordion duct can be attached to the vent-side of the PSU and to the top or side of the case, with a fan on the case-end providing intake for the PSU. (This is assuming that the usual exhaust-fan-only type of PSU is used. Gut the box before you do any drilling!) To provide cool air for an overheating processor, connect an accordion duct from your processor fan (blow-down or standing blow-through coolers only, as there is no need to do ducting for exhaust because there should be a fan sitting right next to the processor for that purpose already) to the side of your case. Make sure the duct is long enough that you can open the case without too much trouble. You may want to put some sort of air-filter on, and maybe even an additional fan on the case-side. This can be done without the duct as well, and will provide cool air to your processor, but will add some turbulence to the already existing airflow inside the case. Is your RAM overheating, or do you just need another intake point for cool air? On the top or bottom of the case above or below the RAM could be a good place to blow some air in. This is too early in the airflow path to do any exhausting yet, though. You’ll be cheating your CPU and northbridge, not to mention your AGP and PCI cards, out of much needed air. Keep these fans on intake only. You may even find it somewhat beneficial to mount these fans on a wedge of some sort so that they point toward the back of the case slightly, making them contribute to AGP/northbridge/CPU cooling.

I don’t know how to write a conclusion for this aside from reviewing the major points. Big fans, simple layout whenever possible, reduce clutter as much as possible, cooling is only as useful as the equipment it cools. Bye.

Heh, very informative. I should look into attaching a fan to the front of my case and reversing airflow for the rear. I also have a blowhole, which I assume is good due to the fact that heat rises.

You'll need to reverse your PSU fan too, then. If it has vents in the front, those will then exhaust, and the fan on top will exhaust that heat from the case.

This is a hypothetically retarded idea, but would you be able to keep a tower cooled and functional if it were in a freezer of sorts? not that you'd do such a thing...

Open your freezer, pickup the first bag of chips and notice all the icy buildup on the packaging...

chilvence said:

Open your freezer, pickup the first bag of chips and notice all the icy buildup on the packaging...

I don't keep chips in my freezer.

-E

POTGIESSER said:

This is a hypothetically retarded idea, but would you be able to keep a tower cooled and functional if it were in a freezer of sorts? not that you'd do such a thing...

You stole that from me on #zdoom

Taken from #zdoom logs

[16:52] <wacky> I've always thought about going to the mall..
[16:53] <wacky> And getting a minifridge for my comp
[16:53] <wacky> WOuld that work?
[16:53] <Faint> heh
[16:53] <Faint> yes it would "work"
[16:53] <wacky> heh
[16:53] <Faint> possibly...
[16:53] <wacky> But I'm not kidding
[16:53] <wacky> I'd drill a hole in the back
[16:53] <Faint> you'll want a freezer
[16:53] <spank> probably you could fit the parts inside a minibar or something
[16:53] <wacky> For the wires
[16:53] <Faint> you'll also want some kind of airflow
[16:54] <wacky> I'd pay about 40 bucks tops
[16:54] <wacky> I'd drill some vents in the side

i have spent considerable time getting mine right.
and it works wonders.
my cousins computer was an absolute bitch. while CPU, RAM and video cards where safe the drives and PS where all compressed into a single area, with no airflow. i ended up mounting the hard drive on the far side of the system, near the top. allowing ariflow to come in the front between the floppy and CD-R drive, into the PS and out the back.

this was a desktop system that was small and compact.


as for over heating i have not done that sence and older pentium board. but then agian i dont overclock.

Some very good points. I do have a silly, as always, question:

What is too hot?

I have an Athlon XP 3200+ not overclocked. My ambient room temp is 27 C (81 F). The CPU is running at about 57 C (134 F) and the MotherBoard temp is at 33 C (92 F)on an untaxed system running Windows XP. I've been told to get it down to the 40'ies (104 F) on my CPU. I can still do some fiddling with my case, but am I in a danger zone?

I guess I should be OK since the max temp is 85 deg C (Die Melt Zone is 90 deg C) and a good rule of thumb is to be at least 20 deg C below that.

Any ideas or opinions?

POTGIESSER said:

This is a hypothetically retarded idea, but would you be able to keep a tower cooled and functional if it were in a freezer of sorts? not that you'd do such a thing...

No, condensation buildup can occur and then you have problems. It's like using liquid nitrogen, sure it works great, but it dies in a half hour because of ion migration in the processor, with a freezer it doesn't freeze as quickly anyway, and once you take it out of there or whatever, the crystals melt, and you bridge connections. Not good.

etimmerAZ said:

Some very good points. I do have a silly, as always, question:

What is too hot?

I have an Athlon XP 3200+ not overclocked. My ambient room temp is 27 C (81 F). The CPU is running at about 57 C (134 F) and the MotherBoard temp is at 33 C (92 F)on an untaxed system running Windows XP. I've been told to get it down to the 40'ies (104 F) on my CPU. I can still do some fiddling with my case, but am I in a danger zone?

I guess I should be OK since the max temp is 85 deg C (Die Melt Zone is 90 deg C) and a good rule of thumb is to be at least 20 deg C below that.

Any ideas or opinions?

CPU Idle temperature should be around 85F, and I know when I play games it goes up to 120-130F. If 134F is your idle temperature, then there's a problem.

insertwackynamehere said:

CPU Idle temperature should be around 85F, and I know when I play games it goes up to 120-130F. If 134F is your idle temperature, then there's a problem.

Wow!!! You are really cool. Is that what everyone else has? It just doesn't sound right to me. Man I'm WAAAAAAAAAAAY off.

ideally you are in the high 30's low 40's celcius range at idle, and nowhere above 50C at load.

I just recently installed a Radeon 9800 Pro, and ever since, I've been running with a side panel off my case - so it doesn't get too hot in there. Obviously this isn't a permanent solution, so I'll need to install some fans - My computer's been running fine for the past year without any case fans (or problems). Now, as it is right now, with the side off the CPU runs at 38 - 45c.

The problem is, I only have one power point for a fan, and it's on the other fucking side of the board:


Solution, anybody?

chilvence said:

Open your freezer, pickup the first bag of chips and notice all the icy buildup on the packaging...

You don't put it in the same freezer that you are storing ice in, and there has to be some way to prevent other condensation from forming in there.

Sephiroth said:

i have spent considerable time getting mine right.
and it works wonders.
my cousins computer was an absolute bitch. while CPU, RAM and video cards where safe the drives and PS where all compressed into a single area, with no airflow. i ended up mounting the hard drive on the far side of the system, near the top. allowing ariflow to come in the front between the floppy and CD-R drive, into the PS and out the back.

this was a desktop system that was small and compact.


as for over heating i have not done that sence and older pentium board. but then agian i dont overclock.

You shit. That was an opportunity to skim money off the top. Order the guy a decent case, but say it's $20 more than it is. Heh.

etimmerAZ said:

Some very good points. I do have a silly, as always, question:

What is too hot?

I have an Athlon XP 3200+ not overclocked. My ambient room temp is 27 C (81 F). The CPU is running at about 57 C (134 F) and the MotherBoard temp is at 33 C (92 F)on an untaxed system running Windows XP. I've been told to get it down to the 40'ies (104 F) on my CPU. I can still do some fiddling with my case, but am I in a danger zone?

I guess I should be OK since the max temp is 85 deg C (Die Melt Zone is 90 deg C) and a good rule of thumb is to be at least 20 deg C below that.

Any ideas or opinions?

The cooler you can run, the faster you can operate your equipment, and the longer it will live. There are tools like CPUBurn and Prime95 -- the former taxes your CPU to test your cooling scheme to make sure you won't burn up your CPU if you do any heavy gaming, and the latter is a stability test that makes sure your CPU is cranking out expected results on some heavy calculations.



Dest: You can strip and splice multiple wires to one connector. Just make sure to "match the colors." Also, there's only so much that connector on your board can tolerate, so you need to get the amperage/wattage/voltage for those fans, add them up, and check your motherboard's documentation to see if it'll tolerate that sum. THIS WAY IS MUCH SAFER, THOUGH -- Get adapters to connect the fans directly to your PSU. You can do it in series with passthrough cables so you only use one connector coming out of there. Connecting to the thing on the motherboard has the potential to draw too much power through and fry the motherboard, if not everything else.

You may also want to mount an intake fan on the front. It might require some case modding, but the cooler air being passed toward the processor will help lots. Cool air has more capacity to take on heat as it passes than hot air does. From the looks of your diagram, those fans by your CPU are exhaust only, right? That creates a vacuum in your case that will have air coming in through every crack. With an intake fan powerful enough to give you positive case pressure, you can prevent that, and also supply a greater quantity of cool air, and on top of that you can put a dust filter over the intake fan to prevent dust from getting in. Lining your case with some kind of filter would be a bit harder to do.



I just realized something I left out of my original post. For those that want to use extremely high-powered but loud fans, you can get vibration dampeners (search VDK-80, VDK-92, VDK-120 on NewEgg) and DynaMat - a noise insulator for cars, which you should be able to find at any local audio supply shop (ask for it) and line your case with so the noise from the fans is tolerable. It basically works by weighing down your case so the vibrations from the fan noise aren't repeated by the case itself.

Ultraviolet said:

From the looks of your diagram, those fans by your CPU are exhaust only, right?

Well first, those fans aren't auctually there, that's where I'd like to put them, and one would be intake(bottom), the other exhaust(top).

And second, Yes, I'd like to find a way for them to connect to either a molex or something else on the psu, as I don't think I'll ever find a case fan with a pwr cable long enough to reach all the way across my motherboard.

Thanks for your reply, deffinitely learned something :D

Twist & tape works fine for short cables. Get yourself some good wire strippers.

I don't know about having intake so close to exhaust. That would serve to cool nothing but your CPU, and poorly at that. If you could put an intake over your processor (assuming the fan sitting on the processor is down-blowing) it would give it plenty of fresh, cool air, and the rear fans could do all the exhausting. To equalize pressure, add an intake fan on the front somehow. If you have to do any case modding, it might be easier to stick it on the top of the case just in front of your PSU (which will also provide some cool air to be filtered in through the front vents on your PSU).

Depending on the computer store, you can obtain fans with the motherboard plug (two or three wires) or the power plug (four wires) or with an adapter. If all of your power connectors are already being used, just get a "Y" adapter so that you'll have one more. But yeah, trying to run two fans off of one plug from the motherboard isn't a good idea.

Piezo said:

But yeah, trying to run two fans off of one plug from the motherboard isn't a good idea.

Depends entirely on the fan. The connection for fans on this ancient motherboard here supports up to half an amp, and the two fans I've got running on it only use up about 0.2 amps, so...

Like I was saying before, check your documentation.

UV wanted me to look over this so I did, maybe I'll give some more info later, not really in the mood right now

You should have seen the smile on my face when I saw in my user profile that Katarhyne was the last poster in this thread.

auxois said:

UV wanted me to look over this so I did, maybe I'll give some more info later, not really in the mood right now

cookied?

Aux taught me lots about cooling. Kinda was a starting source...

I would think that if you just took the humidity out of the Freezer. Then you wouldn't have a problem..and they already make freezers that have built in humidifiers...you store meat in them and you don't get freezer burn. So i would think you could get a mini fridge with the same shit.

Yeah, there's gotta be some way. If nothing else, you can use a freezer as a cooling point for ducting cool air to your intake fans. There would be no heat to produce any kind of moisture in there, unless I'm missing something here. Anyway, the air being heated in the computer would be moving along so condensation wouldn't (hopefully) form and settle...

Getting a little mini-AC and hooking it up to your computer would probably work even better.